Dropbox Rewind is quite a good feature, and one for me to know and let know (as usefull as Apple's Time Machine).
It's almost perfect, but it seems to me that an improvement could be to may access the hystory by date and not only week by week.
When you are searching for files in a single folder, it's really easy and convenient. But, when you have to "rewind" 90 folders on 12 weeks, the number of "click" is quite unbearable.
Hope this can help.