Obliterate Fight

Golgari always feels like its meant to balance the most notable parts of black (kill, graveyard return) with the versatility of green creatures. Your deck is cool, don't get me wrong, but it does kinda seem like a b/g weenie deck without any heavy hitters. Maybe try something like Questing Beast instead of mandrills, sakura tribe elder instead of naga vitalist, or undead gladiator instead of dross hopper. All these creatures are low cost, high reward, and offer additional benefits besides just muscle. Also consider that the less the average mana cost is in your decks, the less you're likely to need a lot of nonland mana production. Even having just a couple dual lands can make things a lot easier, and they don't need to be expensive.

Also, in a deck like this where your removal depends on your creatures being stronger, its probably a good idea to go with deathtouch heavy stuff and make sure you have at least 3 of each variant of fight card. Creature like Gifted Aetherborn, Hapatra, Deathcap Cultivator, Deadly Recluse, and Thrill-Kill Assassin all have deathtouch, and keep with the Golgari Flavor while being relatively inexpensive. Also, Vampire Nighthawk is ridiculous and would be perfect with this. That way, you're taking advantage of the best shit each color has to offer, without losing any overall power. Could also add some graveyard return like victimize, stitch together, or vigor mortis if you want to retain that "sacrifice for power" feel., without having to buy something like regrowth.

I do see what the idea with the obliterator was, and admittedly, people thinking roughly the same thing are probably why he's stayed so expensive for so long. My suggestions are of course, just suggestions.