>>35312528B/W is really hit or miss, on one hand it has the most new Pokémon out of ANY generation, on the other it has NO returning Pokémon until Post-game meaning it is the closest you will get to that "fresh" G1 feeling in regards to discovering new pokémon at every corner provided you hav't already looked up the Dex, and that includes Pikachu for the record, on the OTHER hand those same thing are somethiing people see as flaw, B2/W2 are sequels and best enjoyed after B/W and also can have a optional Challenge Mode the improve the NPC teams greatly.
X/Y has HUGE amounts of returning Pokémon and choice of Pokémon with a HUGE Regional Dex but few actual new ones, but kinda suffers from the QoL things adding up to a point where it is effortless, it is also the leap to 3D, it also adds a "Super Mode" to certain Pokémon if they hold the correct item that may or may not be veering into Shonen, it.
OR/AS is RS (NOTE: RS, not E, No Battle Frontier) through a XY lens.
S/M: No reason to play these anymore at all since US/UM exist and are near identical but ultimately inferior, with some things it did better (Antagonist for example), best described as "THANKS FOR BETA TESTING LOSERS", honestly skippable.
US/UM: No Gyms, instead Trials (Basically challenges and puzzles that vary, but don't have a specific building) and Totem Pokémon (Single uncatchable wild Pokémon that start the fights with a Buff and can call companions for 2 vs 1 fights), arguably the hardest fight in the series history, but SLOW not only due Tutorials and Cutscenes around every corner but also due framerate issues, SM and these also have a SUPER MOVE ONCE A BATTLE mechanic, Some say it is good, others are VERY loud about how these coupled with SM are terrible.
So, if you don't mind or even want new Pokémon and want a more meaty Post-Game go B and the B2, if you don't like new ones but wanna catch many old Poges and can actively hold back then XY. I'd argue against skipping any myself(Except S/M).
