Eregion was planned to release before Moria as part of Shadows of Angmar. It got delayed to the Mines of Moria expansion launch. Turbine did not have enough resources so Lothlorien was not in the launch package for Moria. We could not reach even the launch stub for Lothlorien unless we had Moria because we had to pass thru Moria to get to Lothlorien.
Originally Posted by Planker
For a time Lothlorien was part of the Mines of Moria expansion. Sometime after the launch of F2P, Lothlorien was removed from the Moria expansion. Lothlorien became VIP rental content or you had to buy the Quest Pack.
Lotro expansion only give you one region. Some expansion regions like the one in Rise of Isengard is one large region with two areas that got their own map.
Unless stated otherwise, all content in this post is My Personal Opinion.