Can't really argue with any of that. That said, I'd say the Gal-R might be joint 1st for survivability, what with it's impressive turn rate when separated as well as it's +1 Engineer slot. Having given the ship a bit more of a try, I've warmed to it a bit.
Forgetting the offensive capabilities of the Excelsior for a second, it's got to be one of the most enjoyable cruisers to fly (outside of a separated Gal-R).
If the rumoured BO station rethink of the old tier 5's goes ahead, it'll be interesting to see where the Sovereign will end up being ranked. It may give the ship back it's self respect or doom it to the scrap heap.