she is a awesome ship. strongest hull ever built by starfleet, and thanks to the upgraded one basically having all new tech inside story wise it makes sense. As it is really not a old ship, just a strong re-purposed frame with up to date killer equipment and weapons and armor.
Basically the only part you got right was the usefulness for DOffs, which doesn't matter since you can do all that in 15 minutes anyways (if you're patient that transwarp won't amount to crap).
Don't ambassadors (maxxed tier diplomats) get to transwarp lots of places on any ship they fly? And can't you still grind/max diplomacy through non-combat exploration missions (along with DOFF missions, making the grind even faster than when I ground it out on three separate characters way back when)?
The Excelsior is an amazing ship, and having that ensign engineering slot is way more valuable than having another tactical ensign running tactical team. Probably the most fun ship in the game. Why you say?
Just pop in 3 purple tech doffs and run to copies of AuxToBat. Vola... my TT is on it's global cooldown anyway, and when I need a nice hull heal, I can use ET instead. For PvE just load up 3 turrets and a torp of your choice in the rear, and 3 single cannons and torp in the front, and set up your LtC tac to have TT1, TS2, CSV2... all on their global cooldowns, and you win. It's amazing.
Everything else you do to tweak (Omega/Rom rep stuff) it just is icing. Try using the rom science flow rate consoles, plus the Maco set to get the tetryon proc (and spec into flow cap). Add in disruptor weps and enemies melt in front of you.
It turns better than the other crusiers mentioned, and even 1 degree matters (plus less inertia), plus you get transwarp to everywhere. What's not to love?
In terms of PvE I almost never die in elite STFs, and output almost as much damage as the escorts running near me. A lot of people over-tank their cruiser builds, when it's not really necessary, or simply because they don't have a great BoFF layout (as this ship does). The Excelsior is that perfect sweet spot between just enough survivability and just enough damage to be a real threat. Regardless of what people say, fair or not, it's the best cruiser in the game (if you know how to use it).
Now start yelling, in your best Sulu voice, "FLY HER APART THEN!"
2 Important points. 1st is she costs less zen then the other top tier cruisers 2000 vs 2500. 2nd is she is one of the 3 c store ships fed side available to level 40 characters. The fact she is dog ugly is moot IMO. She is effective.