Map Selection in Matchmaking

I’d just like to understand the underlying system, or, in the absence of a system, the underlying reasoning for which maps go into the selection - and why more than half the time the map that was just played is in there again.

I know the three-map-choice is something of a Halo trademark, but am I the only one getting bored with playing the same maps over and over again, sometimes two or three times in a row? With Halo4 only featuring up to six maps (7 with DLC on BTS) for each game mode, the three-map-choice inevitably forces repetition of a map by the third game.

In some gametypes it feels as if there are only two or three maps in total, and those same three maps show up for the next game and the next, and so on. And the frequency of the DLC maps in the normal rotation does nothing to improve that. I mean, what’s the point of having 7 maps to choose from in BTS, and then play Exile five times in a row?

Shouldn’t the game at least try to not have the same map being played again and again, to inject some variety into the rotation? I know people have favorite maps, and when that map comes up they can vote for it.

Personally, I’d prefer a system that does not allow a map-repeat until all other maps in the rotation have been played - or at least have been offered in the selection. Of course, that would only really work if the map selection would be limited to two-map-choices for every game.