The question is would they need a dedicated starship? Or would they just use which ever starfleet vessel happened to be available?
Surely it would be easier just to use which ever vessel was available.
I agree. However, it seems that the Enterprise
(now the Sovereign
) is often considered the flagship of the Federation, both symbolically and often actually.
Earlier, though, I think Starfleet Command had envisioned the Excelsior
-class ship would be the diplomatic ship of choice, so one of this class would probably have been the UFP President's flagship.
But, with the retirement of most Excelsior
-class ships, that question is open for discussion.
What about a Prometheus