WulPack

I'm personally mixed on your dark mode suggestion ... but not because I wouldn't want a dark mode.  In fact, on my smartphone I use a blue light filter and switch to dark mode for many apps.  I love dark mode to ease the strain on my eyes.  
Keep in mind that for all of your examples of dark mode, the developer controls one user experience for all users. 
For IPS communities, however, individual communities can develop and customize the theming to their hearts content, and that can include any variations like regular or dark mode.  
Will IPS earn major street cred for coming out with dark mode? Yes.  But is it something they need to do or should it be left up to the themers? That's a little more nuanced.