Unless those non-UWP apps are browsers that use non-Microsoft rendering or javascript engines. I don't think that's a dealbreaker, especially when they'll let

Unless those non-UWP apps are browsers that use non-Microsoft rendering or javascript engines. I don't think that's a dealbreaker, especially when they'll let people trade from 10S to 10Pro for free. But it's a pretty big caveat that got added very quietly.