Gen Ranking? Here's mine from best to worst (although I like them all).
II: This was as perfect a sequel to Gen 1 that you could get. It threw constant surprises at you. Oh you beat the Pokemon League? You're only halfway done. Oh you got all the Kanto Badges? Well go to the top of Mt. Silver and watch as
the best thing in the entire Pokemon franchise unfolds before your eyes. I don't think a single game in the series since has ever had a moment of discovery as magical as that.
V: As tired as many people are over classic, charming and fun things getting a "gritty reboot" nowadays, Gen V was probably the best way Pokemon could ever have gone down that route. With a region consisting of entirely new Pokemon without any old ones for the entire main storyline of Black and White and a somewhat more serious story that shed a new light on Pokemon while still keeping true to the spirit of the series, Gen V was an excellent iteration of Pokemon.
IV: A lot of people disagree with me on this, but this Gen actually has some of my favourite Pokemon designs in the franchise. Torterra, Staraptor, Rotom, Gliscor, Rampardos, the list goes on. This was also the first gen where I really began to get invested in the storylines of these games, and really started to look forward to the big Legendary Pokemon confrontation moment that ended up becoming a series staple.
I: Mostly here for nostalgia. As broken as Gen I is, it's impossible to hate. It started it all. It's definitely notable for the magical moment where you discover that your Rival became the champion and that he's the final boss. I can't say much more about this gen that others haven't already said so I'll just tell you to go
listen to old tunes like these and remember the magic.
III:
This gen honestly has some of the best music in the franchise to me. Unfortunately, it's pretty low on this list because it felt like a huge step down from Gen II. In terms of story content anyway. I give it a lot of credit for taking a huge step forward in evolving things mechanically. This was the beginning of Natures, Abilities, Hold Items (or could you do that in Gen II?), etc. All of which would become essential in the competitive scene. On the other hand, there was a large lack of post-game content. The Battle Frontier is nice, but it certainly doesn't top going to Kanto!
VI: I don't hate Gen VI. I don't. Really. I like all the Pokemon gens. However Gen VI is at the bottom of this list because, well, it feels severely lacking. I hope Sun and Moon offers a way more expansive regional Pokedex in terms of new Pokemon. Some things about Gen VI honestly felt kind of lazy to me. I mean, no Legendary Trio?!? That's practically rule-breaking Game Freak! Yeah, there was a lot of good expansions to competitive battling and multiplayer like Super Training and the Friend Safari, and while I genuinely love Mega Evolutions, they only go so far. Gen VI just needed a bit more of an..."oomph" to it, if you know what I mean.