As there is only 1 pokemon game, I don't want to invest in them any more, but I can check out some reviews how the series changed.
And I do mean the game series.
The anime has nothing to do with the games' canon, or progress, or mostly anything.
So, there was red/green/yellow/blue/pikachu/eeevee/firered/leafgreen. It was a grindfest, but the idea was good considering the technical limitations, it even delivered for its time, I think.
The definitive version is Red. Despite obviously Red starting with a picachu after all, the yellow version's protagonist is Yellow, k?
Gold/silver/crystal/heartgold/soulsilver added a daynight-cycle, threw out the overcomplicated and struggling puzzles, modified the pokemon pool, gave a real postgame (throwing a pokeball on a mon in gen 1 was a joke), unfortunately took away a lot of happening for the sake of time-related events. They also threw out the "cath 'em all" slogan, here you don't gain enough EXP to lvl up and lead through all form-changes your mons, and there are no quests to encourage you to, trading pokemon with NPCs also lacking. Although I preplanned to not catch the stupid mons to be honest.
The definitive edition seems Crystal, purely for the full pool, as the story does not differ
, and Suicune was made part of the story there.
Ruby/sapphire/platinum/omegaruby/alphasapphire I heared threw out the time-related jizz fortunately, and integrated both version of evil team. I feel this was a good idea, making the experience of the split games athand of the player (at least on paper, no idea how it went in real). They threw away the continuity with gen1-2, so it is a reboot so to say. The pool got mixed of course, won't mention this any more.
The definitive edition is emerald story-wise, sounds a bit letdown they changed the champion's character for that though.
Here they also added some more stupid randomization of stats (I never looked at the stats), and ... pokemon food? I never give my team any consumables if I can avoid, so limiting my options there doesn't help your case. The double fights just give even more real life luck factor, so big nah.
The post-game sounds fun.
Diamond/pearl/platinum: the definitive version is platinum? Well, the start was in gen 1-2 that "10 years Ash Katchum", and gen 3 "you saved me, here is a bioweapon, go fight terrorists", here found a mixed balance.
Sadly the double battles are still there. The strangest thing seems how the base motive for the enemy boss is changed from the games to the anime series.
The graphic is definitely updated.
The worst thing related sounds this gen games being slow. Slow walking, slow animations, slow story... Oh,and don't forgettocatch a beaver forHM-purposes they all say. Crap, it even has the real-time crap back
Black/white/black2/white2 - sounds a bit greedy, eh? Not just 1 merged version, but new versions of the originals? Can I take this as a sign of degradation? the franchise loosing its steam, hm?
The Enemy Team is not a shady organisation anymore. the gym-leaders have civil jobs too.
No optional areas, linear progress, to much story?
X/Y: too easy? still restricts on the main appeal, mega evolution forms?
Sun/moon: does not let you play. Feels like that Gorky17-look game with HoMM design, which had every turn every character blurped some randomness you had to click away to getdone with the turn...
...
pikachu/eevee: instant remote access to all cathced pokemon? new special hardware device restrictions to be able to play the game? Another gen1 remake? Leave me alone.
---------------
Yes, Black/White/black2/white2 were definitely cashgrabs. They tried to sell part 1-2 based purely on the story. Don't make me laugh.
There was also no improvement on the hardware. Seems every"generation" also ment a new console - except for this four. Lazy, lazy Nintendo.
So, I just found out b2/w2 are gen 5.5? b/w/b2/w2 are either not a new gen given no new console, or b2/w2 a completely new gen given their story is not identical to the original games...
b2/w2 seemed to even want to get rid of the "become a pokemon champion" theprotagonist simply fighting the local team of problem, showing no intention competing the traditional way according to bulbapedia.
PS: the b/w game(s) are the last existing on roms, and the next "two" generations exist on a new 3d-console,which of course no actualy 3d, but are using 3d textures. Well, Doom could do that, hack, even Wolfenstein could do that.
And to be honest, I'm nota fan of this 3D, makes seizing up the map pretty hard, and given the puzzle-mechanics you WANT to be able to see as much of the map as you can.