(INTRO)
Well , for starters, this build isn't too much different from your everyday Naya Midrange. It focuses on bringing out threats that, if left unanswered, can spell doom for our opponent's life total. Our biggest focus here is to use as few creatures possible each time, so that we avoid giving opportunities for 2-for-1's that favor our opponent.
Of course, this doesn't mean that we will just keep one Scavenging Ooze, and never actually cast the Wild Nacatl in our hand unless the first creature dies. Our strategy, as with almost all decks in Magic, changes depending on the situation.
(EXPLANATION OF THE BUILD)
This deck focuses a lot on dishing out lots of damage even from early on in the game. Our ideal scenario is a T1 Nacatl, with a T2 Birds/Caryatid, so that we get ahead in terms of both damage-on-board and mana available.
However, the parts where the deck shines is in midgame (and late game if our opponents is a heavy aggro). Cards like Hero of Bladehold and Loxodon Smiter are made to put a lot of pressure, while Scavenging Ooze and Qasali Pridemage are there to hate on decks like Affinity, Living End, Melira Pod (okay this one not as much as I would like to) and Storm.
Moreover, the planeswalkers used are selected so they can help in both offense and defense. Gideon's +2 can help us get back in, or win, a damage-per-turn race, while Elspeth can help in making a comeback, by letting a heavy hitter fly over blockers, and get even heavier (Although, how much heavier can a fully-armored Elephant Soldier get ? o.O). Chandra, Pyromaster is mostly there for crippling blockers and maybe give us some card advantage, if we are in complete control of the battlefield.
A change I made in this deck, and never regretted, was putting in Stormbreath Dragons instead of Thundermaws. Although Thundermaw Hellkite kills small flyers (Lingering Souls etc.) , Stormbreath Dragon cares about almost none of them. Angels, Lingering Souls and Spectral Procession tokens and other white blockers are unable to block this beast. Moreover, he evades O-Ring and Path, making up for his reduced power compared to his Thundermaw cousin.
(SIDE-IN, SIDE-OUT)
Well , knowing what to put in during a "sideboarding session" is easier than deciding what to take out, most of the time. In this part, I am only making suggestions, as our "less useful cards" might differ on some occasions.
VS WUR Control
-2 Mirran Crusader
-2 Gideon Jura
+(2-3) Thalia, Guardian of Thraben/Hushwing Gryff
+(1-2) Boros Charm
This match-up requires hate on the basis of their deck, which is either tons of draw/removal spells or, in some cases, lots of ETB effects (Vendilion Clique, Snapcaster Mage, Venser, Shaper Savant).
VS Living End
-2 Qasali Pridemage
-2 Hero of Bladehold
-1 Chandra, Pyromaster
-1 Elspeth, Knight-Errant
-2 Stormbreath Dragon
+2 Rest in Peace (you may also use Tormod's Crypt in SB)
+2 Thalia, Guardian of Thraben
+2 Hush Wing Gryff
+2 Boros Charm
A rather simple, yet somehow hard match-up, we need to hate their Graveyard as much as we can, and not let our Scavenging Ooze be killed. If possible, we should avoid using it on Game 1, so our opponent is more likely to use Beast Within on another creature. If we can get some mana ramp and Thalia down, we have earned us some time to make some crucial attacks.
VS Affinity
-2 Stormbreath Dragon
-2 Hero of Bladehold
-2 Gideon Jura
(Depending on their build :
-1 Chandra, Pyromaster
-1 Elspeth, Knight-Errant)
+2 Wear//Tear
+2 Deflecting Palm
(If planeswalkers get side-ed out:
+2 Thalia, Guardian of Thraben/Boros Charm)
Well , Affinity is maybe the fastest aggro deck in Modern, at the moment, which means that we most probably won't be able to afford spending more than 3 mana on a single spell. If they use a build with many non-creature artifacts, Thalia can give us a small advantage that will probably fade if they haven't side-ed out their Whipflares. Always keep Deflecting Palm for a heavy hit from a Cranial Plating-using creature.
VS Storm/Splinter
-2 Hero of Bladehold
-1 Elspeth, Knight-Errant
-1 Chandra, Pyromaster
-2 Mirran Crusader
-3 Lightning Helix
+3 Boros Charm
+3 Thalia, Guardian of Thraben
+3 Hushwing Gryff (if against Splinter Twin)
+2 Rest in Peace (If against Storm)
+1 Wear//Tear (if against Storm)
This is where Thalia really can shine, if we play our cards right. Combo decks are almost completely emphasized on digging their cards for the combo pieces, which means that they generally won't use much removal, apart from counterspells. Our objective here is finding the right opportunity to cast Thalia, Guardian of Thraben, who will earn us enough time to start casting threats. Alternatively, he should do our best to prevent the combo from being put to work by using a well-placed Rest in Peace, against storm, or a Hushwing Gryff on a Splinter Twin who got careless with their mana.