Of course there is much less need in a turn based isometric game, but having the option isn't a bad thing as long as resources are not taken away from other features and it doesn't restrict any design choices. World interaction and inventory management would be easier with a mouse, but can still be done with a controller.
I don't think it's possible to make a deep, isometric RPG for game pad use without redesigning a lot of core functionality. A great example is Skyrim. Great RPG and game in general, but the interface is absolutely terrible and the whole game feels "dumbed down." It's the same with Oblivion and Fallout 3. I'm pretty sure this is why Bethesda moved fallout away from an isometric game and made it a first person shooter. Action RPG's can get away with controller support because they have minimal environmental interaction.
That's basically it. I wouldn't use it, but I don't mind it
as long, as it doesn't harm my PC experience, as Skyrim did.
