In all honesty I don't see any issues with current map cooldown, but as Tesla pointed out 13min for one map that's quite a lot, and if map is pain in the ass it's even worse.. (not to mention destiny maps... - which are deleted as far as I know.)
So.. if anything, set map cooldown based off on how long it is or how much likes/dislikes it has (assuming that you can do that), Alenator/pickup marker maps are fun, people repeat them and they buy them.. putting up cooldown on these would be lame (imo), NTS.... well that's NTS, no need to say anything about it....