I agree with David. I like the change, especially the table (nice work!). Though a lot of the text is well into TL;DR territory. If the welcome message could be half the size that would help, and the formats have some redundancy. For instance, hidden service descriptors and bridge pool annotations have just one sub-header so they could be combined with their top level header.
Hmmm, now that I think about this some more I wonder if the two of us should do some collaboration on this. Stem's descriptor page and CollecTor both provide differing general information...
Stem - https://stem.torproject.org/tutorials/mirror_mirror_on_the_wall.html
* What is a descriptor? * Where do descriptors come from? * Brief summary of the most important descriptor types * Library comparison we're working on
CollecTor - https://collector.torproject.org/index2.html
* Detailed listing of all descriptor types * Reference users on where to get 'em
Perhaps we should combine parts of both for a "New to descriptors? Lets give you a very simple, short description of them". Your table would be perfect for that.