The more I've run tables over these last 5+ years, the more I've found that the addition of all the class and subclass features plus additional character options like feats have greatly reduced the number of times magical item effects have been used or cared about by my players.
When you can do entire suites of special abilities just from your character itself, the stuff you get from magical items just no longer holds an interesting or ultimately useful place in the game. On the one hand that's good because you are now no longer beholden to the whims of the DM and can make your character the way you want to... but on the other, it does reduce the amount of "reward" a character can get for adventuring other than just strict XP. If the stuff you get from XP through the level-up process is just as good/useful as any item you might acquire... the narrative aspect of adventuring kind of gets lost. They adventure to get better at adventuring, not for any tangible rewards. But if you didn't use feats and instead put all the special features you could get from feats into various magical items... you could possibly get the best of both worlds.
Not insurmountable by any stretch, but it does affect the focus of the game and the way characters approach the world.
