Would it be easy to write a script for my idea?
If it's something that is very easy to do with scripts, chances are it won't be built into mIRC. (This isn't always the case, but should be considered when posting your idea.)

Maybe it's easy for you or qwerty to script it, but like I said numerous times, not everyone knows how to work with COM Objects. I would not classify scripting registry manipulation as an easy task for the average mIRC scripter.