So far the only thing that I absolutely hate about 1607 is they forced the darn lock screen on system wake up, even on devices that don't have a password. For me this is a non issue personally, but for devices that I've set up for accessibility for users who have very limited ability it is a huge problem. Screen turns off for power save mode, they hit one of their switches to wake it up, and sure the screen comes on, but it is stuck at that lock screen that they are incapable of dismissing. Simply clicking the mouse or hitting a keyboard key will dismiss it, but they can't do that. Every Windows version up through Windows 10 1511 could be set to not "lock" after waking up.
Thanks MS for being downright stupid here. I've tried a dozen workaround ideas and so far nothing aside from not letting the screen to go to sleep - which negatively affects battery life - avoids this problem.
*edit* I should clarify, it seems to only affect certain system configurations. My desktop PC at home does not have this problem. But the Surface Pro 4 - which these users have - does. Why, MS, why does your own product get messed up like that? Sigh.