Any reason to warrant disabling upower ? Almost all DE's power managers depend on it so there's a good chance people already have it installed. Also upstream enables it by default, since we strive to provide vanilla packages I went ahead and left it as is in the new version.

I think I'd see two reasons:

a) consistency with the previous builds, so it not just starting pulling in upower on systems that doesn't had it beforehand.
b) I think light-locker is especially popular on systems not using and DE, but (like in my case) pure awesome WM or i3 systems. That's actually how I figured that the dependency was added, because as long as upower is present, energy widgets will be used (i.e. on my laptop machines), but on the desktop there's no reason to use upower, so I basically use the installation of the package as an indicator whether you want energy widgets and management. But of course I could work around that, just wanted to raise it as a general topic, that most non DE users might not have upower installed on systems without a battery.

I don't have strong feelings into removing it or leaving it in, just a slight tendency to stay consistent with the previous builds, but if more people think it should be kept as a forced dependency, I won't object :-)

Fair enough, it seems light-locker doesn't link directly to upower, so it should be safe to list it as an optdep. Just pushed an update, you may remove upower from your system once it lands.