ban -k is justified because it's highly common to kick with a ban. In fact, you're far more likely to kick when banning than not. Notice that for this reason /kick doesn't have a -b switch, because kicks don't always come with bans, but the large majority of bans come with kicks.
Quitting a server with a message to connect to another one, however, is a use case that I think probably applies to... 5% of cases? Maybe I'm overexaggerating.
The point here is that if mIRC were to have a switch to execute some vaguely relevant command for every other command, we would have hundreds of switches littering every command-- and then, when mIRC has a *valid* reason to add a switch, the letter code that best suits it would be taken, complicating the interface.
Maybe in the future, /server -q will stand for "quiet" and hide the *** Notices and MOTD? I think that would be a better meaning for "-q", personally. (this is not a suggestion)