Why is there no AI hard mode?

Now, correct me if I'm wrong, but Coop VS Ai is meant to be a fun way to play non competitive as well as to learn new champs or practice. This is how i perceived Ai matches at least. But I've noticed how painfully easy the matches VS bots can be. Why is there not a "Hard Mode" for AI give give more challenge? When trying to learn a new champ and/or learn to play said champ with team coordination, i find that the bot games end far too quickly and there is truly not a challenging battle in which to hone the skills you are learning (or work out a viable style and build play). And jumping into a normals PvP is all well and good.... except that it can be far too hard to learn anything VS players as most just play their best in PvP. So i guess what im trying to say is, Riot, in all yoru wonderful creative..ness... if possible please find time to create a much more challenging Ai mode. ALSO can we possibly see an ARAM style Coop VS Ai in the near future?? (Just a side thought there as that could be fun too) Please feel free to comment or give feed back/Ideas aswell everyone!!