There's also logic (of balance), if item X or spell Y is so powerful, then a different item of similar value is expected to be approximately the same. These kind of expectations are violated frequently enough that people get upset. Another balance issue is the crafting synergy in the game. Using different crafting schools together offers moderate rewards at first, but then "suddenly" accelerates, so it's possible to accidently get yourself to a point where all the challenge is gone. If this wasn't your intention, then you're going to be unhappy. And despite what some people think, it's possible to do this naturally--it depends on what your personal taste/threshold is for challenge.
So yeah, if one person can't imagine playing below Master, and another can't imagine playing above Adept, then you're going to end up with wildly different and contentious ideas about what being overpowered means.
