Gen 5 > Gen 3 > Gen 2 > Gen 6 > Gen 4 > Gen 1
I count remakes in the gen they were introduced originally in.
Gen 5s are easily the favorites. B/W 1 have the best plot, characterization (including N who's probably the most well developed and has the most depth of any Pokemon character in the VG canons). The gimmick of having only new Pokemon until post E4 was a move that paid off. It had no required HMs, the most differences between games, dynamic music, a fun endgame twist, all gyms having a theme of having the gym styled around their profession, likable rivals and was fairly well paced. BW 2 didn't have as much innovation as 1 but it made up for it in having lots of content, hard mode (even if the implementation was pretty crap), no roamers (a mechanic I absolutely loath) and being the first time they made a proper sequel instead of a third version.
Gen 3 has the best region, introduced Battle Frontier, introduced Double Battles, and fun sidegames like Bases and Contests. ORAS added in a bunch of cool lore and has the best soundtrack of the series
Gen 2 fixed and balanced a lot of RBYs issues, great rival, and was the first gen with an actual postgame. However Johto is probably the weakest region of the series and Kanto was so severely watered down due to hardware limits, there's not even a Viridian Forest in there! The level curve is also really wonky. I like HGSS a lot and it smoothed out some of GSCs problems while also having some of the best UI and sidestuff. However I was super bummed that this was the first game to cut out the VS Seeker and that Kris had been replaced since Kris had a special place in my heart, due to her being the first time I could play as my gender in Pokemon.
Gen 6 is alright. I mostly enjoy the technology advancements like trading and battling on the fly online and the graphics overall more than anything else. It's got some crap pacing and the worst rivals but a few moments I did enjoy like all the special camera angles, customization, and AZa shtick.
Gen 4 was slow, poor type balance, felt kinda stale, and too many HMs. Team Galatic is also probably the most unmemorable team for me. It's got a few things going for ot and Platinum improved some aspects but the 4th Gen was mostly saved because of the HGSS remakes
You probably know why Gen 1 is at the bottom so I won't say anything except that despite its numerous flaws its still pretty playable. And as far as remakes go I really enjoyed the Servii Islands quest and would love for something like that to come back