Just an update of my Exchange activesync problem: it turns out that the problem is also present in every CM11 nightly released so far, so it goes back to 4.4.1 at least. As it seems that I'm the only one experiencing this problem and no one else is able to reproduce it, I simply gave up and went back to OMNI again, hoping for a future resolution.
MacKay OMNI is simply too good to leave it!
Someone posted it out on google products forum and i tried it and it works.
Go here and to get the file
This is a common problem with KitKat, even google is saying to go install a third party exchange app from the play store because exchange is broken with Kitkat