Most of the static site generators have serious usability problems. They are simply not usable for many users using WordPress today.
Usability problems like what?
Understanding of the command line, delayed WYSIWYG feedback loop, FTPing/synchronizing files. Some generators don't even tackle "pretty, easy to install templates a la Wordpress" either.
All surmountable, but I haven't seen an "all in one, easy to use" fix yet.
I'd love if I could recommend a single client-side app for people to use that did it all. Something like Coda but tailored for beginners?