Gametype idea: Full Built

I'm sure we all know the feeling of wishing you had an item or an ability before you've leveled up or have accumulated enough gold to have it. This creates an important aspect to the League of Legends game dynamic, and that is: good players level up faster and get better items, while bad players take more time to reach full build. However, what if that wasn't the case? What if each champion got to select their build at the beginning of the game, regardless of the cost?

I suggest a gametype that allows players to do just that. It could be used as an important tool for players to discover what builds work best for them. Personally I think that the game is more fun when most of the players are full built, there's a lot more abilities and passives happening, everything is mostly teamfights, and it all happens so much faster. I understand that there are a few problems with this, namely the fact that the game would be over after the first ace (so likely after the first teamfight), and in certain cases teamcomp would simply conquer skill, but there are also ways to fix these issues. Each player could be given an extra slot for a resurrect SS, or the turrets/minions could be buffed. Either way I'm sure that Riot could find a way.

So there you have it. Does anybody else like this idea? Am I missing something that makes this idea just awful? All thoughts and opinions are greatly appreciated.