I thought it was a nice depature from the usual routes as well - from my limited perspective often an average person enters and becomes very powerful. Not that that can't work, but if the focus is high schoolers and fannish people with no social life, it gets dull for me. The transformation aspect into a different body provides some much needed change.

Idk why, but isekai have been popular recently. It is essentially a portal fantasy - and you could certainly argue Digimon or other Anime also fall into this. I think Sword Art Online probably helped the genre along because it was so popular - but don't watch it, it's a horrendous story.

If we talk European Fantasy or DnD inspired manga and anime, my absolute favourite right now is Delicious in Dungeon or Dungeon Meshi. The party of adventurers loses one of their own to a dragon and they decide to go on a time intensive trip back into the dungeon to rescue her. They are short on money, however, and decide to eat what they find in the dungeon instead of packing rations. It's a really intruiging mix of cooking manga and monster ecology, in a sense. Idk if it has an anime yet, however. If it does, I can only recommend it!