Quoted By:
Big evolution trees would suit Pokemon so much better than the rigid system we have now. Think about how many Pokemon you haven't used because they're available too late in the game, or their evolution method is postgame only for some reason, things like that.
Imagine, for example, you can catch a basic dog kind of Pokemon in the early routes. Depending on how you raise it, it can evolve into Yamper, Rockruff, Greavard, Maschiff, Lillipup, Riolu, Elektrike, Houndour, Snubbull, or Growlithe. You'd be able to catch any of these Pokemon at various points later in the game as is appropriate to the locations, but if, for example, Growlithe is only catchable in a lategame location, you can still use one early because you caught the basic dog.