A question ban can be lifted only if you improve existing questions, see here.
However, there might be situations where it is impossible to improve existing questions, namely if the user has posted only great (impossible to further improve substantially) and horrible (impossible to improve, only worth deleting) questions, but no mediocre (possible to improve) questions.
Some of the disadvantages of this system are:
- It makes it impossible for some users to get out of a question ban.
- It encourages users to post mediocre questions just in case, so that later they can get out of a question ban by improving these questions. These questions can remain mediocre for any amount of time, including forever.
Is there no better way?