They are not trolls, they're cheaters. Autofilling champions has nothing to do with the botting problem, bots also infest the vs.ai game mode, so if you get rid of aram the bot players will simply move to another game mode and ruin that.
I've never seen a bot in aram, perhaps you just need to climb a bit higher to get rid of them, that's not me excusing the situation Riot has allowed so far, just trying to help. If you really hate bots so much why don't you complain about what actually causes people to use bots? Bots only exist to grind exp and ip, remove these systems from the game and bots will disappear as well. Of course that means Riot would have to give up their profits from selling boosts and champions so that's not likely to ever happen.
I don't want aram to go away, its the only game mode I enjoy apart from the vs.ai. It only having one lane is part of the fun, there are no useless distractions in that mode, just fun teamfighting.