I just finished playing through the newest free mid-level (low 40s) zone they recently added: The Angle of Mitheithel.
It looks great. It's connected to the Trollshaws, so it has that nice autumn forest aesthetic. I don't think there are any new assets, though. It's all recycled mob models from elsewhere in the game, which isn't surprising for a free zone.
The quests are bland in terms of mechanics, but the stories are pretty interesting if you're the type who actually reads them (why are you playing this game if you don't?!). For example, there are several literal "Kill X enemies" quests. Not even specific enemies, but "Kill 4 enemies in the zone." Then "Kill 8 enemies in the zone." Then "Kill 16 enemies in the zone." All the quests consist of either killing things or collecting clickable groundspawn items.
The stories are pretty cool, though. There are two main storylines in the zone. One involves an elf preparing to leave Middle Earth, and he kind of takes you on a nostalgia tour of the zone from his centuries of life. It's almost sad to visit ruins and hear him talk about how happy and full of life they used to be. The other involves the rangers (big surprise) and the local wild folk.
It's worth doing if you have a character at that level, but I wouldn't bother going there with a max level or leveling up someone specifically for it.