Well it is a long time coming and glad it finally got here.
If you guys are getting in an uproar about this, think about how the manufacturers are going to do this and how the improvement can be achieved. They didn't say every truck nor did they say every configuration but they will baseline the trucks low and show the improvement with that baseline.
Right now the average MPG of tractors is I think 6 (maybe 5.5), so if there is say a 25% improvement needed, that is 1.5 mpg to give a 7.5 they have to squeeze out of the truck which is very doable.
There are a lot of ways that the truck manufacturers can get more energy out of that oil we burn, they are learning all the time and my search for a new truck, I borrowed a new one a couple weeks back for a day of driving and that got 12 mpg, the salesman claimed 7.5 with 80k behind it if it was driven sanely.