There were requests for controller support in the PC version of Divinity 2. 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 an editor would be missed with a console version; the design / intent isn't really compatible. There are probably editors for racing games, etc, but anyone wanting to create anything with an RPG editor would want to do so on a PC.
ForkTong said in the original post the question was coming up due to Steam announcing SteamBox and upcoming cloud based gaming services (potential markets focused on living room gaming, where a controller is easier to use than a keyboard and mouse).