I admit I do miss the tone of the older games. There was a kind of simplicity to them, but they also felt very unique and unlike other games out there. I do enjoy the later games, especially Sun/Moon, although I find the story side of things less interesting overall. Pokemon was never about a story for me, it was about travelling around, exploring a new world and catching Pokemon, with the linear 'progress bar' of gyms and the Elite Four. I don't mind the story, but it's not why I buy the game.
That said, I don't know if it would be feasible for them to go back to the old style of gameplay - they've moved into a different area with the Pokemon franchise overall and that's a good thing in many ways, with more complex combat, better graphics, more bits and pieces on the side. I don't have the love for Moon that I had for, say, Yellow or Silver, though.
