I like grotto because it comes into play untapped and, like Larry Swasey said, it makes a wider range of initial hands keepable. Frites doesn't really need a ton of mana, but it definitely needs the right mana. Grotto, however disappointing, helps with this and also allows us to be less all in on Birds of Paradise.
I've been running the below list for block zombies. I think its strength is in the aggressive curve and consistent mana base. I've seen a few folks 3-1 a DE with a similar list, and I'm doing fairly well in the 2-mans. Sideboard is in flux.
The meta seems to be focusing around different iterations of BWg token decks and R/W Humans. Seems like a Jund list that goes heavy on Blasphemous Act, Sever the Bloodline, and Curse of Death's Hold would be well positioned, along with cheap removal like Tragic Slip and Geistflame. Tree of Redemption could also serve as a delaying/catch-up tactic. Thoughts?
4 Isolated Chapel
17 Swamp
1 Vault of the Archangel
4 Gravecrawler
4 Geralf's Messenger
4 Diregraf Ghoul
4 Highborn Ghoul
2 Bloodline Keeper
2 Bloodgift Demon
2 Mikaeus, the Unhallowed
4 Altar's Reap
4 Tragic Slip
3 Sever the Bloodline
2 Curse of Death's Hold
4 Tribute to Hunger
2 Witchbane Orb
1 Sever the Bloodline
4 Naturalize
2 Ray of Revelation