I know they seem to totally re-write the code with every release, but seriously, if you could build webflow on top of zurb’s foundation, that would solve so many problems I am seeing: designing for larger than 960 grid; mobile first design; designing for web, email, apps…
(that shouldn’t be too hard, should it?) 
Webflow is a great tool though. The best I have seen for making complex web design easy for non-programmers.