If you click "Badges" overview in menu or you see some users' badges, you just see a very, very long list which is not very synoptical. Wouldn't it be much nicer to present them in hiearchy? For example:
Nice question -> Good question -> Great Question
Notable question -> Popular question
In general, that could lead not only to a tree, but to more general acyclic graph - because one badge may be subset of more badges, but also two badges might be easiest version of one badge.
The badges could also be placed into groups, like
Answers Questions Promotion Bounties ... Funny ... Other
That would be nice, wouldn't it? What are your ideas?