Regardless of how you use it I think a limit on the number of queries that can be (remotely?) opened would be great. mIRC could lessen the effect of drones and flood bots (on clients) by implementing such features without the need for scripts. "Allow a maximum of <N> query windows" and "Send other queries to the single message window" would be nice additions to the options menu.
A scripted solution:
on *:open:?:{ if ($query(0) >= 25) { dqwindow on } }
would turn on the single message window when you have 25 or more open query windows (you *can* open more on your own accord, this will simply stop messages from users opening a new window). When you have things under control (ie when you've stopped being a arrrrh me hardie pirate :P) you can put things back to 'normal' with /dqwindow off
