Well, everything might not work perfectly as many things (though little) changed from 4.3 to 4.4. Yup, most of those things (radio,etc) change, flashing a cm11 rom wont change those and cm will most likely need them. Better to upgrade to 4.4. Also, does ART (new kitkat runtime) need anything new from kernel or anything? I don't see anyone who seems to have tried this and might mostly not work.
Also, What root trouble did you have? Easier to solve that issue than deal with any new issues that might arise from this.