I like it! I've been considering making a Svella deck for a while, I love Red Green decks, but I do already have a bunch of big stompy decks, so she's been getting pushed down the list. But she's a really cool commander!
Looking at the list, I feel like I'd wanna see even more, bigger, phatter creatures: Svella's ability costs eight whole mana, so if you're spending eight whole mana you really want cards that are worth that much or ideally more. I feel like I could see getting some disappointing batches of four here.
I'm figuring [[Emrakul, the Promised End]] and [[Blightsteel Colossus]] [[Craterhoof Behemoth]] are maybe way over budget unless you're good with proxies. [[Worldspine Wurm]] [[Apex Devastator]] [[Kozilek, the Great Distortion]] [[Stonehoof Chieftain]] are also a bit up there, but there's worse in here. [[Etali, Primal Conqueror]] [[Impervious Greatwurm]] [[Apex Altisaur]] [[The Tarrasque]] aren't too pricey at the moment. Not a big creature, but I've seen [[Sandwurm Convergence]] put in some great work.
You probably also want some ways to cheat things from your hand, since you'll end up drawing some of the big spells inevitably. [[Elvish Piper]] just got a reprint. [[Last March of the Ents]] could be extremely good, I'm hoping the price goes down on that.