Besides not obeying the preferences of an user who already has a better alternative (xscreensaver) installed, I don't think light-locker is in a shape good enough to be the default. Perhaps even to be included in stretch.
It fails in nasty ways when the session has been started via anything but lightdm, be it gdm3/xdm/lxdm/nodm/sddm/slim/wdm/startx/vnc. It doesn't mention in any way that the user is logged in and locked -- the lock screen is identical to what you see at login. It breaks suspend for a substantial portion of users. It fails to switch VTs when you have multiple sessions. It suffers from crashes that are quite scary in software some people use for security (yeah, there's no real security against physical access, but a screen lock blocks casual people pretty well). You and me know that to recover, one can usually Alt-Ctrl-F1, login on the console and kill misbehaving light-locker process and _hopefully_ get back the session, but I don't expect an average user to manage that. The only reason I see for considering light-locker are doubts about xscreensaver's upstream's mental stability. Which is not a blocker for a piece of free software, as if a conflict escalates, we can fork it as yscreensaver immediately. Thus, if you insist for light-locker to be default, please at least make it an alternative: ie, as the reporter of this bug suggested, make xfce4-session Recommend: light-locker | xscreensaver, and task-xfce-desktop Depend: light-locker | screensaver. Meow! -- u-boot problems can be solved with the help of your old SCSI manuals, the parts that deal with goat termination. You need a black-handled knife, and an appropriate set of candles (number and color matters). Or was it a silver-handled knife? Crap, need to look that up.
