People complained about the universal resource mechanic feeling too same-y, but the real issue was always with giving Encounter and Daily abilities to martial classes. That's the part which "didn't feel like D&D anymore" and should have been fixed.
And yet Barbarians have exactly that, a daily allocation of rage. Granted, it is several uses, but that is still a daily effect... There are one or two other minor 'daily' effects scattered around the martial characters. I don't see people complaining about them now. Honestly, I was never convinced this was a big problem, and other games have also gotten away with it without much comment. I think the issue was more the presentation of powers and the way 'slots' are very up front, so it makes people focus on them more.
In any case, IN PLAY, it was always much less problematic than people made it out to be as a 'white room' sort of problem. Players IME weren't really worried about it, and when a couple of people tried the Slayer they got bored quickly (it is really very similar in many ways to the Battlemaster). Battlemaster, as an 'encounter only' class in 5e is OK, but it really would benefit a lot from having some 'finishing moves', or some way to do some astounding mythic sorts of stuff that would rival spell casting a bit better.
I'm almost level 5 with my current BM, and it is really getting kinda boring at this point! I have basically one shtick where I blow action surge and a superiority die as a sort of 'alpha strike' and then its just mostly deciding between using another superiority die or not with each attack from then on. Frankly one of my combat maneuvers is vastly superior to the other two, 95% of the time, so I really just have 2 things I do, make my attack and bonus attack (two weapon fighting) or the same plus rolling an extra 1d8 damage and granting the next guy advantage (assuming I hit, and that seems pretty easy to do).
There are things that are nice about 5e, the way build choices are varied but fairly substantial and not overly frequent is a nice one. The lack of daily powers isn't one of them.