Would go nicely with WCML in the 70's to 80's. Most secondary Inter City services were Mark 2 aircons, with a few Mark 2 non aircon and Mark 3 loco hauled stock tended to be on the Anglo Scottish services.
There are many variants of both Mk1 and Mk2 coaches that ee currently don't have, especially the buffet/catering vehicles. It would be fantastic to finally see more variety of types but they seem very slow coming in much the same way as suitable locomotive dlc. Hopefully the 3rd party developers will remedy this in time.