I want Castform to have different forms for all weather conditions, not like, it changes in the weather, but maybe you give it an item and it stays as say, Rain-Castform, but has an ability were it's attacks are stronger or it has a defence boost when it's raining? Because of Castform using an item, it wouldn't need the ability Forecast.
Of course, I doubt GameFreak would do that... I guess... perhaps there are some Pokémon I'd like to see other evolutions for, but, Castform so far is the only Pokémon I can think of that would really deserve "forms", and heck, it even has "form" in it's name. Castform. xD