1 - FR/LG Pretty much all you could want from a Pokemon game, minus the online features and re-usable TMs. It improved upon the original games by giving them the gen 3 mechanics, fixing the glitches, and adding a bit more to the game in a generally unobtrusive way.
2 - RSE The campaign was good enough, the map was alright, and the newly added Pokemon were pretty good, but it's mostly just the fucking mechanics that make gen 3 awesome. Gameplay was sped up a ton, you had L=A, and a *ton* of QoL updates.
Then gen 4 came out and slowed it the fuck down, had clunkier interfaces despite having a touch-screen, etc. Gen 4 was such a colossal step down on a mechanical level. >_>
Great: S/M (other than the fucking long-ass unskippable cutscenes) XY (the higher-touch NPCs were a nice feature and helped to compensate for a less interesting campaign) Pokemon Pinball: Ruby and Sapphire
Average: RBY (glitches aside, many of the biggest problems are in hindsight and regarding the rest of the series) DPP (kinda forgettable, but the real problem was the slower mechanics which wound up being even worse in HGSS) Pokemon TCG (kinda shallow) Stadium 1 & 2 (fun minigames, nice array of battle modes, etc) Pokken Tournament DX Pokemon Pinball 1 (the split screen sucked; 2 had a smooth transition) Snap (only real criticism is length, but it's understandable) Pokemon Go (QA is non-existent and many areas are poorly supported, but it actually has a lot going for it now)
Weak: GSC (terrible new Pokemon designs (although dark types were cool), largely just piggybacks off the cool stuff from RBY) HGSS (slow as fuck mechanics mostly) BW (shitty gyms, shitty overarching story) Coliseum 1 & 2 (played really fucking slow. The fixed encounters didn't do it any favors either)
Haven't finished: SwSh LG!P/E BW2 (stopped relatively early, can't remember why. I like that you can get Riolu right off the bat) ORAS (I think I was 4 gyms in) Mystery Dungeon: Explorers of Time & Darkness (played far enough in that I would be tempted to add to great) Mystery Dungeon: Blue & Red Rescue Team (didn't get as far or like as much as Explorers)
You're the worst, Lokarin!
the only good thing about this list is that it has Black and White in the weak tier.