It seems to me that if you have only just connected to a server (regardless of reason for prior disconnect) and you do no have channels on autojoin, then the list is empty because there simply are not any channels that you have recently visited..... To me, it seems like there are plenty of options availible for autojoining channels, rejoining on kick and on rejoining on reconnect and so on.
The only circumstance i can think of at this moment when you will quit and rejoin a network and there will be no channels windows open (where there was before disconnect) if when you close mirc completely. In other cases (connection reset and so on) the channels windows will still be there, and you can choose to autorejoin them.
I guess i dont see much of a use for the recent channels all in all, but that is besides the point i suppose, however it seems more appropriate and potentially useful that is be network specific rather than global. (assuming its network specific and not server specific, if not then i guess that would be my suggestion)