14’s was superior, in fact I made a post about how 15’s removal of extended customizable colors sucks, donno why they broke something that worked great.
Not sure what you dislike about 14’s GUI, it had the most customization of all the others (infinite color options), are you not able to set the colors to something that doesn’t hurt your eyes? Personally I need black backgrounds to reduce eye pain and 14 was the best for that. Unfortunately, 15 removed the ability to have infinite colors including pure black for whatever reason.
All that said, I still think Cubase has the best GUI of all DAWs, which is why I’ve stuck to it. I just wish they would stop changing and breaking things.