When I was playing Closed Beta. I noticed this problem too.

My own personal hope was that when the game came to release. This level 1 to 50 in one zone would be addressed.

Something like the starter zones was say Rank 1 - 20, 25 at a push, but at rank 20 you had the option to go to Isengard. Then Rank 40 ish to the third Map.