Just a couple of items I think would be fun. Note: I am not saying that I think these are easy to implement, this is simply a wish list.
Fun Features that are mostly home game type things:
Add support for Pineapple
Small blind jackpot (every small blind kicks in an extra blind (or whatever) and that side pot grows and can only be won by the player in the small blind.
7-2 game (not sure how this would even be possible in a software game). Plus, not a huge fan of it, but we always do it in our live games, and a lot of my players ask fairly often about it.
Optional tournament tracker website:
Would be fun to have a webpage for a tournament that shows the blinds schedule, clock, chip stacks, etc. I don't know if this would need to be hosted on the poker mavens server, or possibly we could direct poker mavens to output the information to a separate server. Either one is fine.