This is quite an overstatement... If you don't like dead levels, fine, and you're definitely not alone! In a game where classes grant a large number of abilities or boosts, dead levels feels wrong especially if in other levels you get two or more boosts at the same time (this happens in 3e), because they give the feeling of some sort of jerk-like advancement: in one level you get no special ability, in the next you get two, why not arranging them one per level? In such a game, you are clearly right (and I think 5e is probably going to be this kind of game with plenty of special abilities), but in the more general sense, there is nothing wrong with a game where classes (hopefully all of them being similar, otherwise there is potentially a different problem) get sparse special abilities like one every 3 levels, and only get hit points in the other levels. It all depends on what basic design decisions were made for such game, e.g. how hit points should scale, or how attack bonuses should scale, and of course how flexible/complex should characters be in that game.
My general point being, in a game where classes already have most their levels with a special treat, then yes dead levels should be avoided and would feel better if filled with something; but there are also games where in fact dead levels do serve a purpose, and that purpose is to advance special abilities (and complexity) at a lower rate compared to other features/numbers.