The sentiment is nice, but honestly even if it were considered, it would need to be a transitional.. Try it on newer dungeons/trials/raids, see how people take to it and then if they take to it, do more of a systematic overhaul.

With a direct overhaul like this you can just as quickly find yourself swimming in a serious volume of negative feedback, so it's always a large scale piece of work that could ultimately end up going down the toilet if it isn't tried and tested in a PvE context... It's well and good it working in a PvP context, but doesn't mean it would always translate well with PvE.