Especially MC enemies which have good psiVision takes much of the surprise and excitement out of the later game.
Really? Psionics are strong, but they still can't see cybermites, waspites or sectopods. I'd say late-game is all about dealing with the latter. I imagine honest shoot-out wouldn't end in my favor, but there's always the blasters and melee hit & runs.
Personally, endgame arc grown on me. Finally, my rookies can breathe free, they're in no danger. I unleash all my favourite guys and see if they can survive to the victory. Thus the stakes are at their highest.
It's "wait for Ethereals" that's really annoying. Thankfully, now there can be a semblance of strategy for that I outlined before. But some Eth Envoys in MiB base wouldn't hurt, I think. Hybrid-Envoy style. But does it make sense for them to be there?