Well, the capabilities of Star Trek ships vary WILDLY depending on what the writers need to happen. The Defiant had a special attribute that the Klingon and Romulan warships didn't, it's a very special and rare system called "Designated Badass ship for Main Characters". Still being tankier than purpose built capital warships was odd.
I didn't mind it being tankier than larger federation ships that were essentially crew intensive armed science ships. It be kinda of like being mad a PVP destroyer can tear up a much larger RP exploration vessel. I still think multiple Starfleet admirals should have been court martialled for tossing 30 armed science vessels in front of a Borg cube at Wolf 359 with civilian family and crew still aboard. Just 'cause they're smart doesn't mean they're not also really dumb when it comes to certain ideological beliefs and how they interact with the rest of the Alpha Quadrant :p
Still, the Federation arguably has advanced the furthest up the tech tree of that particular 4x game, so it doesn't surprise me that when they finally got around to building an actual warship, they built a very nasty one.
Things various people in the federation should be court martialed and sent to the gulag for:
-Exploding consoles
-not having and dedicated warships despite everyone wanting to kill them
-the holodeck
-the appalling training standards among "security" personell
-not having a contingent of MACO's on every ship
-dissolving MACO
-seriously these guys were the most useful thing since tachyons.
-not having any pockets in their uniforms
-how the fuck do you aim those TNG phasers, they have no sights
-why don't the member planets of the federation have their own fleets? Give them their fleets back!
-making their ships out of tinfoil.
I could spend the rest of the day listing places where the federation has screwed up real bad, but you get the idea.