I remember a time when I was bothered that mIRC didn't update nicklists automatically whenever someone was opped, voiced, etc. Strangely enough, now the opposite is true.
Earlier versions of mIRC waited for you to use a special command to force an update of the nicklist according to special modes whenever such an event would take place. Now, that command seems to have disappeared, and mIRC updates those lists without even waiting for the command.
A complete solution for all things considered would be new comparisons. In addition to isop, isvoice, ishop, and isreg, a new mIRC version could contain wasop, wasvoice, washop, and wasreg. These values would be recorded before mIRC updates the $nick($chan, N, [o/h/v/r/a]) lists, and matter only at On OP, HELP, VOICE, etc events.
