Sry this is my first time posting in this section so here it goes:
It would be great to have a !nextmap feature that one can type during anytime of a round and the person's count would be added to how many this vote there alreayd are. So if like the map ctf_death is played and people don't like it 3 of them would !nextmap immediately and eventually 2 more would !nextmap and (say) 5 is needed to pass the vote. Of course if a player leaves, his vote would be removed - and of course there's a server-defined passrate of, for example 75% or more.
Often I've played a map that most of the players disliked but the map that was voted for some didn't like either so it didn't get through. Also, it sometimes takes a while until more people get tired of the map so they'll !nextmap and add to the vote-pool. Plus, this is really ez to implement I'm sure...