What I like about the original Sovereign is that it is brilliantly balanced. It can be a formidable tank, nearly impossible to kill, maybe even more so than starcruisers and exploration cruisers thanks to that extra tac team you can slot only outtanked by the Odyssey.
It still has some teeth if not really a top damage dealer, but thanks to its 3 tac consoles it can provide some real pressure over Time.
What did you try to do with it, that wouldn't work?
If you want to go a strict damage route, the refit might be indeed the best cruiser for that. You compromise your survivability a bit and probably won't tank more than one enemy (player ships) without support.
Only competitors here are the Excelsior and Galor who turn better and trade ab ensign tac for an engineer.