How could forget the licensing issue? It is ofc the biggest issue, the elephant in the room that #KDE has a problem facing.
I suggest a cold room reverse engineering of the #Qt ABI and API, which is a tall order, and would probably require a fair deal of money, but it could make Plasma libre friendly - and therefore more acceptable by open source advocates.
Instead of Qt, call it Ug - and make it beautiful, libre, backend capable and web-friendly.