At PAX West, I got a chance to play snippet of the Gears of War 4 campaign running on a PC with a mouse and keyboard, and I'm still thinking about it. Not because I'm super impressed with how it plays—it feels and looks like Gears of War—but because of how well it ran.
Microsoft hasn't exactly been hitting it out of the park with their UWA initiative. A few botched launches left games like Quantum Break and the Gears of War: Ultimate Edition running poorly for some players, even a while later, so I consider my skepticism with any future UWA games fairly warranted. But it ran and looked great, and keyboard-mouse controls felt completely natural. As long as Gears wasn't developed specifically to work on that single computer, we might be in for a smooth launch for a pretty cool game.