The rear inside dual is still a pain in the neck. I don't know what they would have done to make it easier, however, if the did modify it----they better do mod #2!!!!. I bought one of the angle air pressure nozzles/ gauge and it works with a bit of work IF I remove the rear chrome wheel cover.
Still, I do manage to keep the air at the proper pressure and luv everything about our ERA 70X.
If it becomes too much hassle, a good tire monitoring system will elevate the time and frustration as the tires do keep really constant air pressure. Nitrogen tire fill is another answer to having constant tire pressure so there are many ways to effectively live with the air pressure frustration!
I just re-read you're post and it came to mind that although I have a 2012 ERA, my Sprinter chassis is a 2011 so perhaps there is a air pressure valve modification that I am unaware of on the 2012 chassis.