I think it would be a good feature. I would personally love it, and it really isn't that hard. Detect where the settings are stored, copy the .bak files and rename the extension to the correct one. (of course there would be more, Patchou would make it alot more professional)
I will tell Patchou about this thread right now.
However, with the increased pressure to release Messenger Plus! Live on time, bugs come first. It maybe a feature for 4.10 mind you.