>Game optimization/ file size

Doesn't matter at all, the only thing that does is if the game plays when you start it. You should not be discussing this as a reason to buy/ not buy the games. It's not a PC game

>Graphics aren't up to par

Doesn't matter. Have any games in the series's past been considered bad solely because of graphics before?

>Amount of Pokemon available

Doesn't matter, but arguably the best games are from earlier generations that had less Pokemon available to you, and the newer games with more Pokemon are less liked.