It's just because of the fact that the maps are new, so they've been given a heavier weighting in the selection. It helps people learn the layout of the new maps, and keeps you from getting played out on the old ones for a little longer. After a while the weighting will be evened out amongst the maps again, and the old maps won't seem as stale, and everyone will have a good feel for the new ones.
In the meantime though, I'm getting pretty tired of playing the new ones over and over too.
I suspect that even though they made a lot of money off this release they probably didn't make as much as they thought so they are ramming them through the system to get sales. Their greed probably got the best of them. With all the glitches and hacks that we have all had to suffer through then they give is an overpriced map pack and only maps