Using $coms to determine how many instances of mirc are running take a lot of time for a script to process.. easy way to define that your mirc is really running and how many instances are, it must be called by a win32_process class (Path property), so if as $mircexe == win32_process path than the script will understand how many processes from your mirc dir are running (no matter how many mircs are running on system, this method will look only for mirc.exe process from your mirc dir).
But if I implicate this script, depending of the system, the script will take a time to process all data and is not benefic.
Introducing such a option in mirc to allow/disallow multiple instances and better to include identifiers like $instances etc. will make all things simplest for scripters and for mirc performance.
I don't think that mirc reached his end of life or is not benefic to make more changes, to improve performance and so on. I think mIRC must go on and to introduce more powerful functionality, performance and other things that make the life of mirc easier
