1) Code completion is really poor...
CodeLite rules in this case!
2) Generating Makefile disabled...
It's very strange that such a useful feature is not still implemented in C::B.
3) Qt support suffers...
No comments.
There is no point in post like yours.
The code completion is poor and this is known fact, but work is done and it gets better.
If you want to help, make some small test projects that show a case where the CC doesn't work.
If there is a bug that really annoys you, try to make a patch which fixes it, CB's sources aren't that hard to read/modify.
CB is open source community project => all the open source rules apply here.
About 2, have you tried the cbMakefileGen plugin?
About 3, have you tried the Qt plugin (don't know its name)? Also if you want to develop QT app, you can try the QTCreator and KDevelop (especially the v4, which looks promising on paper).
Sorry if I was rude in this post and for the bad english.