I highly doubt it. They are not beholden to stick to a 15-year-old fan-created design made for the same continuity of novels that PIC has just actively invalidated.
I always had the impression that the Titan was a brand new ship of a new class that was even larger and more powerful than the Sovereign class, hence its name (‘Titan’ evokes big and powerful. They’re freakin’ Greek gods, for Pete’s sake.) Pocket Books, however, made the odd decision that the ship was named for a moon and wanted it to be small, which I don’t believe was the original intention behind the name. I of course have no proof of that other than my opinion.
Yes that's the reason I thought of a Galaxy class for the Titan, a big and powerful ship, that and I could just see Riker finally in command of a Galaxy class.
The Sovereign class is actually quite a small ship, although it's the longest (due to the nacelles) it's around the same height as a Constitution class and has less volume than the Ambassador class. Size wise the Enterprise-E sits between the Ent-B and Ent-C.