But that's not what you said.

in fact it's probably one of the most consistent Smash games, only losing to Melee imo

I wouldn't call them close to even in that department, either. But if you want to talk about mechanics, then your view of the whole topic seems blurred to me. Melee is deep, way deeper than Ult, way deeper than a ton of fighting games, but it doesn't simply play 'better'. Melee has many flaws in its design past just technical issues be it for players or spectators, about as much as Ult : Puff stalling, wobbling, PS2, L-cancelling, meteors, ledge mechanics (debatably) or simply the barrier to entry among other things.

Also, there's no such thing as an unintended mechanic. Every tech you've ever used is just an application of mechanics and rules of the engine.