Yay, I almost can't wait. I think MsgPlus! 2 is almost perfect. The only thing I think is a bit nasty now, is the organization of the menus. You have to move your mouse a lot to reach the different stuff crammed into the "Messenger Plus! Extras" menu. Not sure how this could be organized better, but you're so brilliant Patchou, that I'm sure you'll sort it out!
Another thing, kind of related to the above paragraph, is shortcut keys. A lot more functions should be available with shortcut keys, especially the "custom name" function. I've asked for this earlier, and ask again: Could it be possible to bind [F2] as a custom rename button on contacts? It's great to be able to right-click on contacts, point to "Messenger Plus! Extras" and then "Rename contact", but just marking the contact and pressing [F2] is a lot easier and more natural, as [F2] is the global renaming key in Windows.
Also, I have some problems with the bosskey feature. Sometimes it just don't work. I'm not sure if it's dependant on what program I'm in, but it seems to be just a little unstable and random. If there's anything you can do to optimize this feature, please do it.
Other than that; great work. I couldn't imagine an MSN Messenger client without Plus!