>>53902642Just watching them run around then interacting with them to enter an Amie mode with mini-games and being able to pet and feed them would be ideal. That's one thing XY absolutely nailed. However as someone who flunked out of game development myself I recognize that is A LOT for one person or even a small team to turn around with anywhere near that level of polish in a reasonable amount of time.
More realistic would be 2d, reusing hgss overworld sprites for the just walking around stuff, some of the animated battle intro sprites while interacting, with pokemon not caring where you pet it or try to give it food it just has to be within the sprite's bounding box, and use emoticons above them or in the hud as a mood indicator. Since implementing the actual .pkm formats (even using pkhex's code as opposed to doing it yourself) to bring in individual pokemon with all their data would be quite a task, simply things like favorite flavor or mini-game stats to be per species or by types. As for what kind of mini-games, stuff like very simple randomized tic-tac-toe or whack-a-mole, games that can seem a bit more interactive than they really are by framing it as you vs your pokemon and can be implemented fairly easily. Early on it'd probably be easiest to have a set party of a handful of pokemon for testing, but once systems are more stable a good way to bring in more pokemon (assuming importing your own from a main series rom isn't happening) is either earn points for doing stuff to buy pokemon from a shop or have some randomly show up every once in a while and ask you if you'd like to keep them.