doctorhydrogen

1. EDH decks generally needs at least a little ramp in EDH, but if you're playing big stompy stuff you need a LOT more ramp than that or everyone will just out-race you. At the very least a Sol Ring, Gruul Signet, and some of the green land-fetch spells. Me personally I'd be running Sol Ring, Gruul Signet, Darksteel Ignot, Chromatic Lantern, Worn Powerstone, Emerald Medallion, Ruby Medallion, Cooalition Relic, Gilded Lotus, and maybe even a Skyshroud Claim, Kodama's Reach and Cultivate.

I'd also probably move up to 36 lands at the very least by adding a Command Tower and Temple of the False God.

2. You have no way to deal with artifacts and enchantments. Any pillowfort enchantment is going to end the game for you (Moat, Propaganda, War Tax, Sphere of Safety) as is any kind of control (Glare of Subdual, Dovescape). You need at least 1-2 ways to deal with enchantments and artifacts, preferably ways to deal with indestructible ones. Deglamer, Fade into Antiquity, Vandalblast would be where I'd start, and maybe consider Decimate or Hull Breach as well depending on your meta.

3. You have no way to handle problem creatures. You can hit someone for 1000 damage a turn, but if they've got a Platinum Angel out it won't matter since you can't deal with it. You need 1-2 ways to take out creatures at least, if not outright wipe the board to start over. Pit Fight or Prey Upon or any red direct damage spell would work for creature removal, and red has a ton of board wipes (Bonfire of the Damned, Alpha Brawl and Disaster Radius) that will probably kill every single creature that isn't yours.

Beyond that, useful cards to consider:

Mage Slayer- Have your big beater deal damage even if it's blocked

Signal the Clans- Two mana to grab three big huge creatures and randomly get to put one in your hand? That's a pretty solid deal.

Monsoon- If anyone wants to Counterspell you they'll have to take damage to keep their islands open to do it.

Lurking Predators- Wait, so I can cast creatures for free every time someone casts a spell? Yeah, I want that.

Last, there area lot of Planeswalkers that work really well in your colors with stompy critters. I'd seriously consider all of the following:
Domri Rade, Sarkhan Vol, Xenagos, the Reveler, Gruul Caller of Beasts.

Mono-colored EDH desk really, really thrive with Nykthos, Shrine to Nyx as a land.

For artifact ramp I'm a fan of Worn Powerstone over Basalt Monolith, ymmv on that one though.

Shinka the Bloodsoaked Keep maybe? It's not awesome, but that's no real downside to having it.

I'd seriously consider both Blood Moon and Stranglehold, not so much to help you, but because how much the eff up everyone else around you.

Dolmen's Gate is very useful in tribal weenie decks because you can be a lot more reckless with your attacks without losing troops. Not sure what I'd pull for it, though.

Swap Naturalize for something that either tucks or exiles (Deglamer, Return to Dust, Revoke Existence, Fade into Antiquity) so you can deal with indestructible stuff (Avacyn, Darksteel Plate, Theros gods).

You have two copies of Darien, King of Kjeldor.

Purphoros God of the Forge is a great enabler for getting damage to play more creatures and giving them haste once they hit.

Breath of Malfegor, Price of Progress, Rakdos Charm, Sulfurous Blast, Volcanic Fallout, Acidic Soil, Blood Tithe, Breath of Darigaaz, Earthquake, Exsanguinate, flame Rift, Molten Disaster, Searing Rays, sizzle, Slagstorm, Steam Blast, Syphon Soul, Pestilence, Pyrohemia and Withering Wisp are all excellent ways to get 8-10 damage on the board with one spell/activation for casting fatties, and Where Ancients Tread, Warstorm Surge synergize well with playing said fatties.

I like Fireshrieker a lot in infect, doubles the applications upon hit and it's reusable if the critter dies.

I guess it depends on your meta, but for me I play people who tend to play either creature heavy decks or token decks, etc. so Do or Die tends to be a much better card than Diabolic Edict, but if you rarely see 3-4 creatures on one team then maybe not.

Whispersilk Cloak for the combo of protecting your general and making him unblockable.

I'd swap Disenchant for Revoke Existence. Yeah, it's one more mana and sorcery speed, but at least in my meta the ability to get rid of Theros gods and Darksteel stuff is invaluable.

I think Celestial Mantle is a fantastic card . . . just not for this deck. At the same CMC I'd rather give +3/+3 to everything via Collective Blessing, or Double Strike + Lifelink via True Conviction. Cathar's Crusade can get out of hand in a token deck and end games fast, too. Basically I'd avoid any aura in favor of global enchantments.

I'd also put in one or two methods to deal with indestructibles, but that may be just my meta, and you may not need them. For me I see Darksteel Plates, Darksteel Forges, Eldrazi Monuments, all the gods, etc. so I need to have ways to deal with them (Deglamer, Revoke Existence, Path to Exile, Oblation, Condemn, Return to Dust, Fade Into Antiquity). You may not see that stuff though, so having ways to get it gone might not matter much.

Partially agree on the lifegain, but not in removing Beastmaster Ascension. You can pretty often trigger that the turn it comes into play with a token deck (with no risk if you're running something like Reconnaissance) and it has to be answered or you win.

Glare of Subdual- Less than a buck to buy, and in a token deck it flat-out wins games.

I'm guessing you don't have the new Elspeth in here because you don't have one or are waiting for the price to fall.

Mass Calcify makes for a nice sweeper in mono-white.

Crackdown is a great way to screw people who aren't playing mono-white.

Reconnaissance lets you attack with the team to make sure you procc Odric's ability, then pull back any creatures you want to have available as blockers.

Infiltration Lens is pretty fantastic in Odric, too. Throw it on some chump token, attack with the team, make six creatures block the token, and draw a dozen cards.

Nihil Spellbomb- Something to consider depending on your meta. Spending one colorless mana to empty a graveyard is pretty great, and if you want to you spend another B you can draw a card. There are times I blow it on empty graveyards if I have spare mana at the end of an opponent's turn just to draw a card because I know I can get it back next turn when something dies.

I'd thin your land base of non-basics a bit, or I would if I was playing this deck at my gaming store. Every red deck I see is running Blood Moon, and that would ruin your day. That may not be an issue where you play, however, so adjust accordingly.

I found I rarely had the power on the board to utilize Mosswort Brige, but our creature base is different so that may not be same for you. Keep an eye on it though. I've become a fan of Temple of the False God lately, too, but again, that might vary by deck.

Okina, Temple of the Grandfathers isn't exciting, but it's easy to swap into a forest spot to make Glissa a 4/4.

Yavimaya Hollow is available for five bucks or so, and regeneration is always nice, especially with a deathtouch general

Couple things that work well for my Glissa deck:

Urza's Bauble/Mishra's Bauble- Forget the ability, it's a zero cast/zero cost way to draw a card. Now, my Glissa deck is all deathtouch with ways to do it remotely (Predatory Urge, Viridian Longbow, Wolfhunter's Quiver, Arena, etc) so I have a lot more ways to kill enemy creatures on demand, but I'd still give them both a look. For me I've had games where a single Bauble has drawn me 12-15 cards, and that ain't nothing.

Jester's Cap- Very meta-dependent, but I have some people I play with that have cards I simply do NOT want to see hit play. Jester's Cap lets me yank Doubling Season/Parallel Lives/Glare of Subdual out of a token deck, then do it again next turn to pull Rooftop Storm/Living End/Zombie Apocalypse from a Zombie deck.

Wayfarer's Bauble- Simply has to go into any Glissa deck that wants ramp. Personally I'd yank out all those ramp sorcery spells (Kodama's Reach, Cultivate, and replace them with ramp artifacts (Horizon Spellbomb, Armillary Sphere, Traveler's Amulet & Wayfarer's Bauble) that can be reused over and over with Glissa on the board.

Ratchet Bomb- With Glissa on the board, Ratchet Bomb should read: tap to destroy every token in play, then put Ratchet Bomb back into your hand. Seriously, in a Glissa deck Ratchet Bomb lets you wipe every token off the board for two mana every single turn.

Executioner's Capsule/Triangle of War- Similar to Ratchet Bomb, Executioner's Capsule lets you Doom Blade a creature for three mana, then bring it back to your hand. Triangle of War might work better in my Glissa deck than yours where every single creature has deathtouch, but even in yours if Glissa is in play it becomes pretty useful.

Grim Feast- Read the Oracle text, not the text on the card. The oracle text says: "Whenever a creature is put into an opponent's graveyard from the battlefield, you gain life equal to its toughness." That is ANY opponent's graveyard. In a four player game this has netted me 50+ life on a board wipe multiple times.

Beastmaster Ascension- Straight up wins games.

A deck this commander-centric needs as many ways as humanly possible to give him shroud/hexproof. Me personally I'd be throwing everything I have at killing Kemba as soon as he hits the board lest you wind up puking eight tokens a turn at me. I see Whispersilk, but I'd find room for Lightning Greaves, Swiftfoot Boots, and probably Mask of Avacyn.

Nice, super similar to one i'm running

I'd replace Disenchant with Revoke Existence, same CMC (though not instant) and it'll get rid of indestructible things your opponent has in play (Theros Gods in particular).

Maybe a couple small creatures (Necropede or Ichroclaw) and maybe a couple of Titanic Growth? Tough call.

Canopy Cover maybe to make them harder to block.

Puzzel Box is brutal; adding to my Niv Mizzet deck ASAP.

Winds of Change, Windfall, and Shattered Perception also make pretty good Niv hand cyclers. Consider Psychosis Crawler, too; let's you double up on the card draw damage.

Cyclonic Rift over Aetherize maybe? Gets more stuff up and off the board when overloaded. Hinder over Dissipate? Let's you tuck commanders into their deck.

Viridian Longbow and Thornbite Staff for sure need to be added, probably Predatory Urge as well. Lure (and the handful of similar enchants) for board-wipe. I'd find room for both Thicket Basilisk and Cockatrice; neither have the Deathtouch keyword, but they do the same job, and they don't even need to do damage. They'll even kill something with first strike. And they're both cheap.

I think you have a little overkill on artifacts, and you'll find you have too many first strike ones out that really bring nothing to the table. I'd remove a few (Accorder's Shield, Avacyn's Collar for sure) and add a little more defensive removal (Naturalize, Murder, Do or Die maybe). Not sure if there's many tokens in your meta, but if there is Ratchet Bomb and Gaze of Granite are great with Glisaa, too.