Tribble puncher wrote:
maybe the galaxy class ship was built as a "fly the flag, rally the people" type ship?
I'm not sure that's a valid design goal since appearances are in the eye of the beholder.
Starfleet seems to like building lighter versions of their ships of the line (Galaxy
-type), so there is some in-universe reason for the paired designs.
In "Tin Man", the Enterprise
-D (and her Galaxy
-class sister ships, presumably) is referred to as the fastest ship in the fleet. The original Enterprise
held numerous speed records, according to Captain Stiles in TSFS. It's possible that the geometries of Starfleet's heavy cruisers are better suited for high warp speeds. The modular pod of a Nebula
might make it more suitable for urgent, extremely mission-specific roles.
Otherwise, just about every starship built by Starfleet is multi-purpose.