Its gonna be an interesting plane to say the least. I am guessing that we will see some Mummies which are just fancy Zombies, right I am really interested in how they are going to represent the God cards. I am hoping they use a different mechanic then with the Theros Gods. Also are the Trial's going to be represented like the Quest cards? (Quest for the Holy Relic, Quest for the Gravelord, ect)
I've been thinking about the new Gods as well, and wondering if they'd do something similar to the Theros Gods. I like the idea of being permanents that provide a buff, that turn into creatures under certain conditions. I could see them being like G.Moto suggested, and requiring additional cost to cast, but I'm thinking something like this:
Sobek, God of Death 3B
Legendary Land Creature -
Swamp God
Indescructible, Hexproof
Sobek, God of Death isn't a creature unless you control at least 3 other black creatures
When Sobek, God of Death Attacks, Each opponent sacrifices 3 creatures.
When Sobek, God of Death deals combat damage to a player, sacrifice 3 creatures.
3B: put a 1/1 black cleric creature token into play
8/8
I think this is pretty balanced, as when he isn't active, he's essentially a mana rock that can spit out dudes to bring him to life.
The other color gods could be similar, but maybe White requires you to have a certain amount of life, green just takes a lot of mana, blue needs you to have a certain number of cards in hand, and red must attack alongside a number of other creatures. Could be a really cool set of Gods, and I can't wait to see what R&D comes up with.