iOS allows scripting and interpreted code-- EXCEPT: you are not allowed to DOWNLOAD executable code. In other words, you could have a scripting language, but you could not allow your users to share their scripts with others. Yes, definitely severely limited.
There are other reasons it would be limited of course-- the lack of proper windowing APIs, as I alluded to before, and the fact that iOS is not a truly multitasking OS, so hitting your home button would disconnect you from IRC. Not really useful to run scripts on a client that can't even run in the background.
FYI Android likely has neither of these restrictions, so it could be done there-- but again, there are no plans to port mIRC to other OS's. Plenty of things would have to change, including the UI, which is one of the major features that makes the client "mIRC". You want "a scriptable IRC client for Android/iOS", you don't want "mIRC for Android/iOS". mIRC wouldn't even really be mIRC outside of Windows, period.
