Why I don't think FTS is a viable skill:
Without pumping any points into stealth skills, I feel just as effective with my bow, silenced pistol, and knife, as I do with maxed out stealth skills and the same tools (in POIs). Heck, pop a squat (or don't, there's not much difference) with a shotgun and take a POI with no points in stealth or shotguns and you will be more effective than a bowman with 3 levels in archery and from the shadows. Because the hard-coded wake up sleepers don't care about your stealth, nor do the outside zombies, and the sleepers that are SUPPOSED to wake up don't until you're basically on top of them anyway - at which point the proximity wake up goes off and springs you regardless of stealth.