I think it would be nice to have a widget that would display recent rank promotions. This could be a standalone widget with more functionality (such as only displaying promotion above a certain rank), or it could be a simple feature added to the existing "User Recognition".
This is something we may revisit in the future, but isn’t currently planned functionality.
I'd imagine that implementing this would require the addition of a "last promotion" time stamp to the character properties. Even though this might be inherent, I'd like to add this as another feature request I'd like to see because a lot of promotions in my guild are based on how long a previous rank was held.