Pretty sure the map voting system already removes a map from the rotation after it's chosen.
Extending that might be pretty excessive.
I agree with the round timers though. On our server, pre/post timer was 15 seconds.
Round were also 3 minutes long, with haste only extending it by about 20 seconds. With the current settings on RND, if you have 12 players, rounds can very easily last over 10 minutes which is too long imo.