Titanfall 2's pacing is among the best I've experienced in the AAA genre in years.

Resident Evil 4 stands out from the rest of the series by its pacing.

Bayonetta 2 has no dull moments and is constantly upping the ante. Titanfall 2 and Doom 2016 do the same thing.

COD 4 Modern Warfare. The campaign is a roller coaster without being absurd like later games and keeps it up the whole way through.

Yeah unlike a lot of its sequels, COD4 knew when to let players breathe. If the action is constantly dialled up to 11 then 11 becomes the new normal and it stops having any impact. That said, I'm not one of those folks who reckons COD went to shit after 4, I still thought World at War, MW3, and Black Ops I and II were good games.

Felt that way about Gears 3. The action all just kind of blurred together after a while.

I don't disagree.  I adore World at War and think it's the most underrated game in the series even if it's not quite as good as 4.  I also like the first 2 Black Ops games quite a bit.  I'm not a fan of Modern Warfare 2 and 3 however.

Super Metroid it is.

One that immediatly comes to mind is Portal 2, which I think exceeds over Valve's other great game, by not having a single dull moment. The first one is a great game, but I felt half the game was an introductory tutorial. Portal 2 just keeps building on itself with layers of complexity in its puzzles. The writing helps keeping the story interesting throughout and no area or chapter overstays its welcome.

Tokyo Mirage Sessions #FE and Xenoblade Chronicles X. They progressively introduced new mechanics that made these games never feel boring or repetitive.

I absolutely love World at War as well, it's dark and unsanitised depiction of WW2 makes it feel like the most truly mature COD game in my opinion.

I didn't like MW2 as I felt it repeated too many of MW1's beats and tried too hard to be edgy and cool, but I actually quite liked MW3 since it reigned things in a little and had some really cool missions like the one where you hijack a sub and use it to rain missiles down on an enemy fleet as you escape through it.

TLOU for my mind. The game does not have continuous action but i felt it did was take the player through the whole range of feelings and emotions as you play through the game, rather than just a single one. Something that is a lot harder to achieve imo.