As a player, I've barely touched that surface. Because I've already mined everything of the least interest presented by it - in prior editions. The freshest class presented in the 5e PH is from 2004, and it didn't interest me then. I haven't played out every possibility in the 3e Sorcerer, but the 5e Sorcerer doesn't offer any of those remaining possibilities. Everything else 5e has to offer for player options I'd gotten enough of from D&D in the 20th century.
5e is wonderful for what it set out to be: an evocation of the classic game. The downside of that is 30+ years of playing said classic game leaves you with very little new to glean from from such a focused iteration of it. You have to bring interest to it, yourself (and, yeah, game of the imagination, that's not unreasonable), it's just the opportunities to do that are, IMHO/X, all on the DM side of the screen.
So, yeah, this 'advanced player' would like to see some more player content.