Idea for a Co-Op vs. AI Hard-Mode!
I think the 5v5 Summoners Rift Co-op vs. AI games can be fun if its a bit of a challenge. I have recently enjoyed making a low level account and playing these bot matches, when someone feeds hard, the bots actually get somewhat difficult to play against and its quite fun.
I suggest you add a harder mode, here are some ideas for making it harder, which don't require making smarter AI:
Enemy turrets get more 'items' aka buffs.
Bot team gets a passive gold increase.
Bots use wards, or rather if its easier to program, wards appear for the bot team in some pre-determined positions, somewhat randomly.
And a bonus idea for making it +2 awesome:
Create some generic grey robot skins for the bot champs which could be unlocked only through playing and winning this mode Maybe some sort of token for each win, and the skins cost tokens or something like that. That obviously would be a bit more work, but +2 awesome, come on.