>>12124540They do that though. 2nd gen had this. 3rd gen had cave fillers like Zubat and Geodude and water fillers like Tentacool amongst new pokes, 4th gen had some new evos/prevos so we got stuff like Roselia etc. It's only 5th gen that doesn't because they're all new Pokémon. But then they had BW2 that had a huge range of Pokémon from all generations. 6th gen will have a mixture of old and new too.
I like the idea of having small weak Pokémon at the start. Gives a nice sense of adventure and discovery.
