I think based on my experience it seems like a good thing. I guess for many games it is included and it seems to be main thing for most of the game. So yes it seems like a good idea.
I actually used to be annoyed because I never got to finish any zone's storyline before I got too high level for it. On the one hand, I wanted to keep doing the quests and get to the end of the story but I also felt like I could be getting more out of the next zone. I haven't played since Legion came out, tho, I don't know if the change in max level helped with that (or if it made it worse)
I have never done power leveling. I have to admit that I never knew about it either and I've only learned it from this thread. I might employ it in the future games I play. It sounds like a good way to finish a game faster.