Consistency is an important goal right now in Plasma, however it should also extend to how consistent the widgets usage is on the backend, too. After all, if we stay on the same type of widgets for Plasma, it'll make things more consistent and potentially easier to maintain, too. Plus it'd be a good thing to move on from PC2 and PC3 to QQC2, especially nowadays with Qt6 on the horizon.
The plan of this task is the following:
- Fix bugs in PC3 before porting
- Port any remaining PC2 things in Plasma to PC3
- Formally deprecate PC2
- Make everything that uses PC3 use the QQC2 Desktop Style
- Port everything that uses PC3 to QQC2
- Formally deprecate PC3
Furthermore, QQC1 is going to be going away, potentially, in Qt6 so the sooner we start transitioning everything to QQC2 the better and the easier it'll be in the long-term future to potentially move to a QQC3 when the time comes.
A lot of work will have to be done, such as testing for visual regressions and fixing them during the porting work, fixing control bugs along the way, and fixing regressions found along the way, but the sooner we start this long process the better IMHO.