How can this be addressed?
I don't know, but maybe paying a developer to implement new interface.
Why not do some inspirational sketches and videos and see if the ideas actually convinces someone.
Or maybe UX as a separate role only works in hierarchical organisations where you only have to convince a few people that maybe don't care that much, don't have to do the work themselves, and might not enjoy thinking out things on their own, just saying...
Also see what happens with Gnome.
What do you mean? I find it a pleasure to work with the Designers. Even though they are paid by RedHat, as a volunteer contributor I feel I have good discussions with them and am happy to implement proposals. They follow up and seem genuinely happy about your contributions.
Do you mean the conclusion that it was in hindsight regarded as a good step forward?
You do know that we, the GNOME application developers, spend a lot of time supporting both MATE and unity to give people the best experience no matter which shell they use, right? Do you feel excluded by our work?
I know this because I am a developer and have a very good designer friend.