Has the Constellation class been suggested for Advanced Heavy Escort\Refit slot? It fits in the theme of the Advanced Tier 3 being an older ship from canon. Also for special ability, The Picard Maneuver would fit perfectly. A fast jump to a new position with an afterimage left to draw fire for a few seconds. The Refit version could have a counter based on the defense created by Data.
She's been designated cruiser in the shows, she's appearently some kind of sucessor to the Constitution and she's obviously too bulky for her era to be an escort.
Even if we don't use size as the only means to determine a ship's purpose ecause that factor changes so much between the 23rd and 24th century, the Constellation is much closer to the Excelsior in her characteristics than any of the current escorts.