I see the process is under way to remove the strange maps from the ladder pool. I've also seen discussion to limit the map pool for new players. Please don't do this.
Bad players become good players by being put in difficult situations. If you limit the map pool you will make improving that much more difficult.
Whenever I start a 1v1 Ladder match, and that loading screen is up, I get a little thrill; I have NO IDEA who I will be facing, or where it will be. I for one enjoy the strange maps. I played Cluster Freak recently - I pulled off my first T2 Air snipe. Also played the Ditch - And learned first hand what a telemazor is. In the face.
If anything, divide up the maps by difficulty, a "Suggested Skill Level" or somesuch. That way, a noob can select them all and throw himself if in the fire if he so wishes. Experts can leave in the strange maps. But the the choice still remains.
Limited the map pool by ladder is solving a problem that doesn't exist. Removing the maps that are strange is unnecessary if you use the "Suggested Skill Levels." As for the unbalanced maps, I leave that to those with more wisdom than I.