I can't judge Exvius' writing in its entirety, as I've only put a couple of hours into it; however, the most important factor so far is that as far as dialogue is concerned, it doesn't read like the Engrish word salads in 13, Type-0, and 15. If anything, it so-far suffers from being simplistic and anime tropey, but that's still better than the former.
I'm 40+ hours into 14. The dialogue is actually good but far too loquacious for ultimately very simplistic communication. In other words, the localization is good, but it's a bit tedious.