>>48106819This. It really clicked for me when someone pointed out that no Pokemon can learn the TMs given out by Gym Leaders through leveling up (except Pikachu learning Thunderbolt, which was added in Yellow), as though the Gym Leaders themselves had developed those moves. Stuff like that really made you feel like you were making the Pokemon stronger as their Trainer.
While I love this design philosophy, there are a couple of caveats: First is that it kind of sucks that enemy Trainers in RGB had such shitty moves on their Pokemon, although I recognize that this was more because of memory limitations. The second is that, if you're going to take this approach, you actually need to make the TMs good. This was more of an issue in Gen 2, where you've got a number of Pokemon who don't get shit for STAB moves until you're basically at the endgame (looking at Heracross here).