How exactly do people objectively rate Pokemon games? They all play the same. They all have the same exact gameplay. They all essentially function the same way. Everything else can be seen as subjective - Pokemon design, region design, extraneous features and facilities. Right?

So how do you objectively say one gen is superior to the other? It's not like the gameplay is changing. You're still playing Pokemon.

Genuinely curious, what determines how good a gen is beyond opinion when all games pretty much play the same way?