Ok, cool. I guess the only pro of having the whole class passed down I can think of then is that you get full auto-complete with Qt Creator that way.

However, I don't see the great benefit of switching to QWidget* other than having one class less to depend on (i.e. one less #include), or am I missing something?

To me it seems to be only a question of how one likes to structure the relationships between the plugins and the main app.