Escorts did not get more tankier.
The top end Escort players learned how to make them more tankier and that information has made its way down through the ranks so even a new Escort player with a modicum of ability to surf the forums will find the same tricks to increase an Escorts survival.
Cruisers where not mysteriuosly nerfed when no one was looking.
Only Science has been truelly nerfed into being subpar.
All of this happened becuase Cryptic can't balance a game they do not micromanage but keep throwing more fluff OP items into at an alarming rate.
The game has become a DPS monster in that burst DPS is the only solution to every conflict and that is why Cruisers seem to suck becuase they do not do burst DPS but sustained DPS.
Cryptic needs to balance thier game by making it viable to do indirect sustained damage that is meaningful without making the Cruiser a Burst DPS vessel that replaces the Escort.
I think the best way to do that without upsetting the system too much is to improve the way that Single Cannons do damage. There is a reason to why they aren't so highly valued in the exchange. People tend not to use them because they don't see much in the way of damage from them. Right now they are more a crit' device than anything else. I think that they should do a tad more damage than they do.