hey denis, indeed it was not possible to extend a core controller when we started to debate. It's now possible. So it should answer to most of your requirements. I gave a small exemple with Global Settings, but you can do the same for Question controller:
github.com/LimeSurvey/LimeSurvey/tree/de...admin/globalsettings


I've started a specific thread about it here:
www.limesurvey.org/forum/development/119...re-class-from-module


About your last questions: this could have been done since years. I could have done it for LS2.5 or for ls3. But because of all the debate around event architecture VS OOP inheritance, it was delayed again and again by carsten to avoid conflicts

Well, now it's done.