If you had full control over Pokemon Gen 8, what would you do? Don't worry about profitability.
As for myself,
>Take four or five years to develop it
>100+ new mons, designs are simple yet organic (not comprised of circles)
>Only a few new legendaries
>2D graphics with smooth, detailed animation
>Difficulty modes which affect how many Pokemon your opponents have, their levels, their movesets, and their AI
>Challenging enough on hard mode to facilitate the use of a full team
>Bring back fan-favourite features like (optional) following Pokemon, a walk/run toggle, ability to rematch most trainers, etc.
>IVs are abolished, Hidden Power is determined randomly upon hatching
>Frequent patches to keep the metagame as balanced and decentralized as possible
>Minimal handholding or free handouts, your character is treated like just another trainer instead of the centre of everyone's universe
>Huge region with a focus on exploration and finding your own way, non-linear with lots of alternate paths
>Story plays out like a series of vignettes where you help towns and characters with their unique problems (think Dragon Quest or something)
>No ubiquitous evil team or absurd apocalyptic scenarios
>No event shit, everything is available in-game or via trade with players of the other version