Well, lessee... the Enterprise-B was commissioned in 2293, and in canon it perished... not sure just when, to be honest. The Enterprise C was an Ambassador in canon, so it was commissioned in or after 2325, ten years from now.
So one choice is to christen the Excelsior in current production as the new Enterprise... or to go without Starfleet's "flagship" until the Ambassador project finishes. I mean, the new ship could simply replace (complete with -B) the lost in time Enterprise.
It kinda feels off to have more than one Enterprise in a given ship class, to be honest. And the current state of the Ambassador project is stage 2:
13 / 20 Final Tactical Frame Design
18 / 20 Final Operations Frame Design
13 / 20 Final Engineering Frame Design
13 / 20 Final Hull Frame Design
13 / 20 Final Warp Suite Frame Design
Now, the first ship of the class... it kinda feels like it should be called "Ambassador", as per tradition.
EDIT: Also, major political and research gain by Starfleet for being quick - very nice.
It might also be somewhat intimidating to other Federation enemies, such as the Syndraxians or the Cardassians - "they declared war and it was over in six months with few losses". Add in the bio-plague response, the success Starfleet had in slapping the Syndraxians down and assorted other actions... well, there might be somewhat fewer attempts to provoke the Federation into acting.