Gen 5 is next in line for a revisit and like with Gen 4, I feel like they would make additional games for this gen. so, here are my ideas:
1. BW remake in a storybook artstyle. The characters and pokemon are 2D but the world is 3D. The game has a paper aesthetic, almost like Paper Mario.
2. BW3, or Grey game. A brand new open world game in a reimagined Unova region that takes place 2 years after the events of B2W2. Works like SV, where you can take on gyms, story events, team battles etc. in different orders.