Including wayland fixes to 5.12, for the lifespan of the LTS and having the same technical policy is absolutely fine.
The problem is calling something LTS has strong implications both in terms of expectations and marketing. I don't want us to try jumping from "wayland is experimental" to boldly claiming "wayland is ready for the LTS demographic" in a single release. It's more that we've made big steps forwards and ready for 5.12's non-LTS audience. Plasma will crash on any use of a QtQuick1 combo box (which is iterally everywhere) without my Qt patches which are not in any release. I get at least two of those bug reports a day right now. Regardless of the state of kwin, with my Plasmashell hat on, we can't put a big "this is stable" badge on it. I'm not trying to be a dick or block your work especially if the bigger faults lies with other components, but I won't compromise on unintentionally misleading users. I want to stick very clear from writing "our wayland support is LTS" on the annoucement. That could simply mean avoiding writing Wayland and LTS in the same sentence. David