Oh, and we can't forget about the tease of Darkwing Duck
Boros has access to a lot of tricky spells, and even if that mana has mostly been spent on Avacyn, theres more cheap interaction that can mess things up, including new format stalwart Deflecting Swat, which can come down for free
That can be crucial in helping plan your next turn - and even the turn after that - knowing exactly what options your opponents have available
Sure, the opponent can remove the Aura and get rid of Griselbrand in the process, but you already got to draw a bunch of cards and rebuild, likely allowing you to return that same Griselbrand to play again
Omnath has a ton of ways to be built, so make sure you use the filters to look at the full pages for each build