But seriously...

What the Ambassador SHOULD be is the T3 Cruiser that you get before the Galaxy class makes its appearance at Tier 4. (Not saying it shouldn't get a T5 refit, mind you)

The Heavy Cruiser (Four Nacelle) should then, in turn, be made the hull type for Tier 2.

Get the Constitutions and ancient, "tall-ship" design theories out of the main line. If they have to be there, put them in the C-Store, with period-appropriate statlines.

(Yes, I'm bracing for the flame onslaught.)