Flying through T5 on Sunday the transit was pretty smooth.
Inbound and outbound PAX ARE kept separately from each other, you have to go through transit security to get back to the retail area. Which involves going up the crazy escalator which someone was complaining about at the start of the thread.
The debacle at the opening of T5 was about the mixing of domestic and international departures and having pictures taken of domestic PAX.
I do think that the T5 security is getting slower, fast track is one of the misused signs i've ever read!