And I don't think there's any reason to make it open source
There's people that would like to see some change in mIRC but they know these changes will never happened.
Open source would make this kind of possible for them.
As for error handling, it depends on what exactly you are referring to. In most situations, error handling can be done very easily with the script that needs the error handling.
It's not about difficulty, rather about how we use it, having to use :error $error and /reseterror is good for one specific alias, not for a whole script or for handling error in general.
A new event for handling scripting error has been asked in the past, Khaled might think it's a bad idea because it could cause more problem than it could solve, like the recursion..
