Recons are great! And canon too. +1 Recon SV would be a nice idea.
Akira +1 would be the only escort that can use EWP1, RSP2 and any other LtC power in high demand and give the Feds a pseudo-carrier, in exchange for a slower turn rate, more hull and more crew. That alone I feel is rather different from what's offered now.
The AE got a +1 version that could separate.
The Defiant got a T5 upgrade and a cloaking device.
What really needs to be done to the Fleet Escort? I'm in a dwindling number of people who feel that the Tier 5 ships are all just about equal (although I admit the Flagships are more powerful than any other Tier 5) and with the oncoming Andorian Escort do you really need a refit of a ship that is competitive? If anything you should be for more Member race ships rather than Federation designs.
I'm even going to say that the Klingons got their Tier 5 +1 BoP in the B'Rel Retrofit that has the Enhanced Battle Cloak. Do they need another ship, sure how about another Cruiser light as a Vor'cha and with the BOFF layout of an Excelsior. Heck make it the D9 (or is it D7?) K'Tinga retrofit. The Klingons would love it. As for an alternative to the Raptor, yeah they have the Garumba but they really do need a Klingon built choice.