Honestly my own biggest complaint in the OS sphere of late is the woeful lack of any unique or innovative options.
I remember in the late 90s, early 00's, when my OS addiction was in full swing, it seemed like there was a dizzying array of alternative OS projects all over the web, and whole sites dedicated to cataloging them.
But these days it's pretty much Windows, or Unix. Everything that isn't Windows, just winds up being Unix. OS X is Unix, Linux is Unix, iOS is Unix underneath and so is Android, shit, so is the OS on the damn Playstation 3.
Unix is goddamn everywhere and in every thing, and it seems like there just isn't room in the world for other options anymore.
I get that the commonality of knowledge and software is handy, but would it kill for some more creative approaches? Shit, even some of the non Unix OSes, like AROS and the other AmigaOS descendents, have been modified to be more like Unix.