Mauro, I couldn't follow your links, but if you mean Susan's work on SSL, that's based on some work I did for a client who agreed that I could (when I had time) incorporate the ATS changes I did back in to ATS. Susan made it work for 5.X and added some additional functionality (e.g., SNI support). Based on a number of discussions with ATS users this work seemed to be of general interest for a variety of reasons. For example, one use case was to intercept SSL for origin servers listed in ssl_multicert.cfg and blind tunnel the rest. I think one of the example plugins does it the other way, white (tunnel) listing clients who bypass interception, another request that came up in my discussions.
The short answer is, it is being done both for improved architecture and because many users have a use for these extensions so the work is being done in as general a way as possible.
