User blog comment:SirAston/LeagueTalk Z - Plan to Eradicate All ARAM-Twinks/@comment-5035765-20140506193849/@comment-5331854-20140506200422

That's what Special Rerolls are for. If the base formula for Specials are similar to those of the regular Rerolls, then you can reroll up to 4 times as long as you get champions you do not own, since you still can use regular Rerolls. This is just a safety measure and while it still gives traditional ARAM-Twinks a slight advantage, since they still rely on a small pool here, they won't get their favourite ARAM-champs in every game.

Also, barrierless trading. You being stuck with a non-tank melee would be a rare problem, especially when a changed map would give melee initiators (which most non-tanks are) an edge, therefore making them more desirable.