I'm not convinced he's as safe and capable as you suggest. Swansea have been awful at times this season defensively. Bristol and Huddersfield spring to mind. Think there's a big chance he could be out of his depth but also feel there's a good chance of being the perfect fit.
Sounds like the perfect replacement for Roy to be honest. If Palace try to play football like us they will be next seasons Fulham they probably need this type of manager but the fans won't much like it.