PF races (have) no reason at all to field an Escort
Well....they literally don't have any reason at all to field an escort, as those escorts don't have any carriers to escort.
When it's all said an done though, I have hard time seeing why incentive HAS to be found to fly EVERYTHING.
If the argument is that PF races don't want to field an escort because they don't want to waste that valuable Combat Support slot on an escort when they have other alternatives, I can see PF race escorts being another reason why there may be a need for a new PBR bucket: The 'only one of these type per squadron' rule.
This would allow a team to supplant a line ship with a ship from this group if they desired. I might have to better explain this: there are a lot of ships in some cases are unrestricted and others that fall in Support that should have some other designation. They're special because they are rare, but not so much so that they should take up that Support slot - which really should only be for true support types. These should be allowed in line slots - but limited to only one per squadron. The Fed DDL would be an example of this. It can fill a line slot, but there shouldn't be a whole squadron of these things. Fast Cruisers are another good example, and I'd probably supplant the new rule I made for them with a more expanded one.
Oh, and about actual carriers: I had been playing around with providing some extra clarity around carrier groups. Don't get too excited, it deals with the small carriers. Right now the rules require both the 2nd and 3rd ship to be Escorts. Well, realistically, carriers built on Destroyer and Frigate hulls - as well as some built on older Light Cruiser Hull's usually only had ONE escort (I think that would include CVE's Corbo). In a 3 ship squadron, that 3rd ship could realistically be either Command, Line or Support. This could possibly make smaller carriers/escorts viable selections without compromising the source material.
While I am thinking about it (and Corbo hinted at it): I think there needs to be some sort of stipulation about the hull size of the command variant relative to the rest of the ships in the squadron. An F5C shouldn't be the command ship for 2 D7's. It's an excuse to maximize the potential of the smaller hulls in a squadron. Just as there is an Escort hull rule requiring that the escort can't be a larger hull than the ship it's escorts, the command ship can't be a smaller hull than the largest ship in the formation - or at least a reasonable compromise, like you can command up one hull class so that a D5L could command 2xD7's, but and F5C couldn't.
So there's 3 tweaks