Yet mIRC is an IRC client - that's it's scope, and always will be.
While maybe half or so of mIRCs regular users run some kind of script, only a fragment of them do write scripts. And I'm sure of these scripters only a fragment is interrested in things "outside" of mIRC (in the sense of "while mIRC hasn't to be running as chat client"). Thus imho only a fragment of a fragment of mIRC users would benefit of a standalone interpreter...
While this doesn't render your request invalid, it renders the issue ... very unlikely. You may like to push mIRC to it's limits and beyond the borders of all chat-related tasks - however: why should Khaled support those in the first place? He's not sitting around bored and asking himself what fancy new thing to add next. There's always been a lot of unchecked boxes on his todo list (e.g. the general UTF compatibility thingie atm, and I fear it will keep him busy for some time to come - but w/o any question a incomparably important issue it is, and at the heart of IRC - as the world has never been ASCII, and it's ASCIInes diminishes every day).

That aside, should a hypothetical standalone interpreter carry over all the (current) limitations o mIRC/MSL, just to maintain compatibility? Wouldn't it (rightfully) provoke a ton of new feature requests, disperse / distract the developmental focus off the main app (and it's hundreds of thousands of chatting users)?
Every task has it's tool, and the devs of a tool ought to focus on it's dedicated function. mIRC may be close to a swiss army knife in many cases, but you'll never fell a tree with it (...not without avoidable pain at least smile ).

All the best, but please don't have high hopes - to me, it's very unlikely to happen.