An option to aim with mouse would be nice, though I do like keyboard aim I think both should be an option. The miss mechanic also kind of sucks since its already reliant on aim skill
Other than that, i think the ability to edit EVs/IVs, have multiple teams saved and the ability to mega evolve during battle, with like a button press or something would be cool
More Pokemon with access to Haze and Roost/Recover would be really good because boost stacking is really strong, I think a bigger cool down between moves that increase stats would be better