1. More starters ( Not just water,fire,green but also dark, psy, ect...)
2.BIG world, where people get lost in
3.Exploration ( Have a vast place without a map a let the player wander around in search of treasure or rare spot )
4.Keep having a bitchy rival : Blue was so perfect on the first games, so annoying and yet so perfect (also multiple rivals would be good, and let those rivals be rivals with each other )
5.Better storytelling, have us team up with the rival at the end...
6.A "reactive world" when Team rocket invades a places don't just let it be, send the elite 4 ! some random trainers ! Champions ! Make the environment feel alive ! ( being alone in an invaded building just feels not right )
7.More random quests and fun NPCs
8.Different type of city then island / village / city, give us more ruins,graves,big roads,airports...