Gen 1, because Fire red & Leaf Green aren't playable on 3DS while Diamond, Pearl and Platinum are.

Gen 4, if we want to revisit Kanto i believe its better to go Gen 2 Remake or make a brand new game.

I want an Emerald remake so Gen III for me

Make a new story on an old region. Hell, if you feel bold enough, make a new story that spans a couple of regions. They have the full power of the Switch at their disposal, Pokemon games could expand so much more.

Sinnoh had a lot of problem. the gameplay was slower, the progression system was slow and unbalanced, and the pokemon were a bit lack-luster. thats why it SHOULD be remade. with modern hardware and mechanics we could get a definitive Sinnoh game.

meanwhile we have the Kanto region. the most overused region EVER.

Gen I - main game based in Kanto
Gen II - entire Kanto region was updated and playable in Gold, Silver, and Crystal
Gen III - Kanto region entirely remade in Fire Red & Leaf Green
Gen IV - updated and remade in Heart Gold and Soul Silver
Gen V - first generation in FIFTEEN years to not feature the Kanto region at all
Gen VI - Kanto starters are made available in addition to new starters
Gen VII - the Kanto region is referenced every 10 minutes and the original games are now on VC.

yeah, im too nostalgic about Gen I. in fact, I feel like it holds the series back. Gen V was the best generation they ever made, and it the first and only time nothing from Kanto was used. we cant just keep reusing it over and over and over again.

Gen 1 - Would be all over it

Gen IV is the one I enjoyed the least, but I'd prefer a remake of that one before Gen I. Sinnoh remade could potentially make the experience a lot better.

Its going to be gen 4 but it should be gen 1. We need that on Switch.

I would much rather a sequel to the Kanto region, as opposed to a remake once more, ala Black and White 2, to which I actually hated, I hate you Speedo Pig evo line... forcing me to choose the non fire type for the first time ever... sorry, rage building.

Go figure, Typhlosion and Delphox are my two favorite evo lines. Though I don't play for the tourney scene, as my breeding love has been a perfect Fennekin, Milotic and skill link Ciniccino.