I have Pinnacle (not installed, but purchased) and I'm sure that there is something out there but Grim Dawn has integrated controller support, but it is extra wonk and feels terrible. I was thinking D3 on console controls, that is not what I got.
Still might be worth a shot to install Pinnacle, see if there's a Grim Dawn profile, and check it out - just to see if gamepad support there's better than what Crate themselves put together. Hey, you never know. [shrug]
Though, I don't know if Crate knows how to design their game just to work well around a gamepad or what. If it's a design issue that's the problem - then yeah, I dunno if Pinnacle or anything can fix how the game's built around a gamepad.
I'd figure most PC players likely will be doing KB-mouse with Grim Dawn, since it does feel like an old-school ARPG for pointing-and-clicking galore, built around KB-mouse like Titan Quest + Diablo 2.