Instead of going on about Escorts/Cruisers, I'd point out that Stahl recently mentioned that warp cores are being added.
And if I had to bet money, warp cores will settle this debate by tying base stats and survivability into a modular unit so that regardless of class, your survivability and damage will be inversely proportional to one another and may come with some serious changes to threat gen and power level management.
This would be cool. Sounds like it will be a whole new console slot...
ODYSSEY SCIENCE CRUISER - U.S.S. MAIDEN TORONTO NX-971312-B
VESTA MULTI-MISSION SURVEILLANCE EXPLORER - U.S.S. HOPE IN HELL NX-902013-A