Good point, if there is one thing this site lacks, that's it! More recognition for citations.
But maybe it's not wise to reinvent the wheel. The "wheel" in this case is the system practiced on Wikipedia:
-  inline marks, as inserted ad hoc by readers, are the most vital part there
- adding citations as needed
- replacing citations by more reliable ones
- no "original research" (not good for history.SE)
- notably, no self-made synthesis of sources, only reporting a synthesis already done in a source (not good for history.SE)
Knowing this Wikipedia standard, how can we improve it for use on SE? How can we integrate it into SE concepts like badges and scores?
It would be great to start something minimalistic, but to get it started at once. My proposition:
-  inline mark, built into SE engine, so other sites besides history.SE could use it
- recognition simply based on presence of this mark - optimistic assumption, that if nobody cared to insert at least one , the text can be regarded as well-cited
- 1 well-cited answer = 1 badge
- It would work for starters only and is totally non-scalable. Later community needs to delete these badges and automatically recalculate a new recognition scores/badges (whatever the "proper" system would be).