Everyone seems to be saying, "Yes, it would be a nice feature, and extremely pleasant and useful but."
1) We need it in all the other applications.
2) We can only get it used in one application, which is hardly any.
3) If there are all those variants, why script it, just make it an option. (I think Riamus implied generic DOM elements in webpages.)
4) You can't script everything, so don't bother; if the docs (the API) were any bigger, mIRC would be unusable.
5) mIRC shouldn't be the first!
Of these, I can only agree with 1. However, as you gather, I can relate to 2-5. Freedom of mouse wheel isn't in my country's constitution, but it's a darned good idea anyway.
If you ask me, the API should be 2-10x bigger.