It's been a while since SSLstrip is deprecated and I see no more options for SSL mitm because of OSCP/HSTS and browser counter measures.. Is SSL so unbreakable to common sys admins?
As the owner of the network I want to be sure what passes through my gateway but in means of data, i.e. not just that IP:PORT is connecting via 443 to this HTTPS site..
Even the last known vulnerability such as NTP Skimming attack requirese many aspects that most modern operative systems "fixed" or are hard to replicate in a real scenario..
Have you tried\Do you have any(recent & working) PoC of defeating SSL via Transparent Proxy/Proxy on your own gateway? (Please don't tell me about sslstrip or copy from google)