Things G2 gave us:
>day/night
>friendship (evos, Return, rewards for maxing)
>crossgen evos
>trade item evos
>different legends per version BUT emphasis on moves, not availability
>two new types
>type chart rebalance
>held items
>berries (including the trees and juicing)
>multi-region (even if stunted)
>prior game follow up details (Koga gets upgraded, daughter takes over, cinnabar erupted, etc)
>face prior protag as toughest battle
>breeding system
>baby pokemon (oh boy merch money!)
>SpDef split
>more move variety (looking at you Bug)
>backwards version trading
>battle tower
>roaming legendaries
>special pokeballs
>split evo families (beyond Eevee)
>catch contests
>room customization
>shinies
>pokerus
>mystery gift
>girl protag (eventually)
>watch & radio (precursor to all devices to follow)
Likely missing more, that's off the top of my head
Feel free to argue if they were good or not, but the step up from G1 was so strong that G3 looked lazy
