New Game Mode: Proving Grounds

Kind of a bare bones concept for me at the moment, but it boils down to a fairly simple idea. Sometimes, players just want to try new champs, or experiment with different runes/masteries/items on champs they like to play, but we do not want to have to try and scream out the role we want in a bot match, or get any team rage if the idea we had doesn't work out when playing an actual match with other players.

Bring on the Proving Grounds. In this game mode, you could either play solo, or with one partner. If playing with a partner, it must be a duo game, single players will not be matched with other single players. You have a base with one exterior turret, an inhibitor, one interior turret, and your nexus. The goal is to protect it for 30 minutes. Every two waves of minions sent from their base will have a random champion (or two in a duo game) that will be equal to the player(s) in level and build, on the intermediate AI level. There is no enemy "base" for you to take out, or anything like that, you simply try to survive wave after wave for 30 minutes.

Passive gold collection is increased by 50% to give you enough cash to make sure you get full build, and xp generation is increased 50% to make sure you hit 18 as well.

ALL CHAMPS will be available for anyone to use in proving grounds as a way to try them out (again without risk of rage factor if you turn out not to be any good with them) so that you can try out any champ you are interested in purchasing.

Thoughts? Ideas for improvement? Questions?

Edit: There would be no ip or xp gain for this mode as it is essentially just you beating on target dummies to try out new ideas.