I don't find FreeBSD that hard to use as a desktop, and can set it up fairly quickly. I'd like for binary upgrades to be more reliable. (Though they get better all the time). I'd like better hardware support and for things like say, synaptic touchpads to work out of the box.
I'd like documentation to be more up to date at times, though now that I think of it, I can't remember anything I've had to look up in the last several months that was really out of date.
Though I would like it a bit smoother on the desktop, I wouldn't want it to go the way of some versions of Linux, where the good things about the desktop start taking precedence over using it as a server. Simple example, RedHat deciding to put no more effort into their curses based installation, so that if one is having video difficulties, or just doesn't have a mouse handy, they have to accept all defaults or else write a kickstart file.
TL;DR, Being able to, with few exceptions, not need to compile, but always be able to use binaries, (but, as this is just a wishlist, still having the ability to fairly easily work with ports or source code for the system itself.)
I'm not sure that flash is dying--isn't Hulu going to keep with it? (And Hulu is supposedly considering offering ad free next year)