Well I wasn't referring to just you, Racoon, _D3m0n_, and Watchdog all said they wanted this feature and that it would be a great feature, however none of them have provided reasons why it is needed and why it is a great feature. To my understanding, if you want to have something added, something that could very well take Khaled a good bit of time to do, then there should at least be reasons for adding it. As it stands now, all we've proven is that you have reasons for using it, and the third scenario you described, referring to being an oper, obviously doesn't apply to most IRCers since they are not opers. I'm just saying, does anyone have a reason why it is useful for IRCers in general?
Oh and about your second point, my response to that would be, if a user doesn't read the helpfile/understand it (which is what you suggest) then the user will most likely not know that /part -n exists and therefore won't use it.