Honestly that's my pretty close to my own feelings about 5e. They did a pretty good job of balancing things without falling into the 4e "Make every class the same thing with different fluff," trap, but it came at the expense of investment via the crunch. When I build a character in 3.5 or PF I have a firm idea of how they fight, how they interact with other people, and maybe even what they do to relax (if the build has space for skill points in things like Profession (Chef) or Perform ([insert instrument here]), or for little bits and bobs that cost a pittance for a higher level character) before I ever start writing their personality and backstory.
When I make a character in 5e, it feels like I'm following a color-by-numbers book. It dumps the entirety of the character beyond the most basic aspects suggested by ability scores into the realm of backstory, which I'm sort of leery of -- it reeks too much of freeform RP for my taste, which at least in my experience tends to be the domain of shitty self-inserts and Sues (not that people don't manage to do that in 3.x/PF, mind you. >.>). That, and pretty much every character looks more or less the same at any given point, distinguished solely by their backstory. That's not to say that backstory doesn't matter, just that it functions better when supported by the rest of the sheet.
I'm of mixed opinion regarding the "four personality boxes" -- on the one hand, they're a good crutch for people who don't care to spend much time developing their character, but on the other they're more of the same shallow paint-by-numbers character creation.
There's also something I've encountered in the magic system. Between the miscellaneous nerfs and those done by way of the new Concentration mechanic, and a vastly smaller set of spells, there are actually relatively few spells worth taking. In 3.5/PF my usual problem with casters is narrowing my options, not digging up enough spells that aren't mehworthy or complete crap. Concentration means that you take at most maybe two or three Concentration-limited spells of each level even if you're a Wizard -- you'll never be able to use more than one total at a time, and you don't get many prepared spells to begin with. But the thing is, beyond that all you really have are a scant handful of non-shit direct damage and Save-or-X spells, and a scattering of glorious rituals.
Ritual casting is pretty much the only purely good innovation in 5e casting IMO, given that it's basically done for the boring utility spells like Detect Magic what unlimited cantrips/orisons did for those.
Arcane casters also smell the most like 4e to me: Wizards and Sorcerers in particular are almost alarmingly similar now because of how spellcasting has changed.