Newer Wayland is easy for you to achieve by yourself without breaking anything (as it's backwards compatible). Update it, test it out, and submit a pull request at https://github.com/mer-packages/wayland when you're comfortable about the quality.

There's a very finite number of people working on these things, and the people working on them tend to prioritize things that give the biggest "bang for buck", which unfortunately for you, is not anything related to X. It's simply not something that the vast majority of customers want, as far as I've been able to tell.

That doesn't mean that those people won't work with you and support, publicize, and encourage your work - it just means they won't do it for you.

It's not like there's a conspiracy to hold the version back, either. It's a case of what was there previously working well enough to not require touching, up until a QtWayland upgrade (required to provide other ongoing work/fixes) bumped the minimum version, so I bumped it too.