For me, the only CRPG characteristic I find valid is the reason why it has a "C" in its name. It is the only difference between a computer and other devices : mouse input. As long as a RPG feels like it has been made with mouse controls in mind, it qualifies.
I'd have to agree here. Keeping it simple, the C in computer. A game designed with a computer Mouse and Keyboard in mind.
Designing a complex party base, stat heavy tactical RPG game around controllers changes so many parameters. You have to dumb everything down to its core. Or make everything extremely annoying to use.
Adapting a game to use a controller is less impactful but still annoying (changes in UI to accommodate controllers...LIKE THAT TOILET CHAIN SYSTEM LOL).
Or just say, screw game pads, deal with it and use your mouse.

Not many devs brave enough to do this sadly.