The only one of DmC predecessors that can claim to be mechanically superior is DMC 4
I mean yeah, on the whole, sure. Yet part of that is because the gameplay based itself on concepts about hitboxes and time windows/frame data DMC3 introduced and DmC trivialized, so for that reason in my mind I included 3 as well, hence the plural. But anyway, change that plural into a singular and the overall meaning of my post remains intact.
and that's mostly in terms of obscure tech, that has no practical use outside of making combo videos.
Practicality isn't necessarily an argument to invalidate depth. Just because a certain set of techs isn't "practical" doesn't mean it doesn't exist. And whether it exists or not is what defines the game's mechanics's depth. Especially in Devil May Cry, where pulling off flashy stuff is what most of the satisfaction comes from, as opposed to just beating the game.
But DMC4 is not just fancy, crazy tech. Even simpler stuff like using animations to your advantage add to the depth, and it can very well be practical. Like, look at this one.
Goes back to the hitbox manipulation thing I was talking about under my first quote. Guy didn't get hit cause Dante's ducking motion during Real Impact lowers his hitbox in a way that makes Credo miss his swing while Dante gets his move off, without having to interrupt it (which in the case of RI you can't anyway) to dodge roll or Trickster dash.
DmC, in contrast, decided to go with gargantuan hitboxes and hurtboxes for both enemies and Dante, which not only threw a good part of execution finesse away, but also streamlined a little too much the level of interaction with demons and bosses (the latter ones especially).