You guys do understand what CAFE standards are right? It's for the FLEET average, not just an individual engine. So ford can have a gas sucking crappy mileage 6.2 and meet CAFE standards, as long as they sell enough fuel sipping economical engines that the fleet average meets the CAFE standards. So they very well could offer a 6.2 again if they return the Raptor, if they're selling enough of the V6's that their fleet average is higher than the CAFE standards.
I understand exactly how CAFE standards work; they are for the entire Ford fleet. F-150s make up roughly 25% of Ford sales. All F-Series trucks are responsible for about 1/3 of all sales.
You have to look at two things:
1) The negative impact of 6.2L mpg on the fleet. Why do you think the 6.2L is so limited in availability now? Why do you think it's such an expensive option? Ford wants to sell as few 6.2L trucks as possible.
2) Economies of scale. It's expensive to have all these motors as is. Having another motor specifically for the Raptor would not be cost-effective.
My last point has nothing to do with government, but just has to do with technology. There are ways to get better power and better mpg out of motor now. The 6.2L is a pig. Technology is advancing. Do I want the next gen Raptor to have the 2.7L Ecoboost? No! But do I want a truck that will be selling in the year 2020 to have an NA V8 getting 10mpg? No! And Ford wouldn't want that either. The 6.2L motor will not be the motor in the next-gen Raptor.