Yes, this is the nail in the coffin.. I'll stick with the Carrack as Exploration is how I intend to spend most of my limited game time. Having a large utility ship is appealing, but this one just moved to the 'aquire in game' category.
It may be a possible substitute for a Caterpillar, though, if you have one...
The Galaxy's cargo module appears designed to hold 16 of the 32 SCU containers, which the Caterpillar cannot carry, and which the RAFT and Hull C carry externally where they can be easily shot off\"removed". You could also stack smaller SCU containers in that space as well, making it more versatile than the RAFT or Hull C as far as cargo transport.
Of course, we don't know what modules the Caterpillar will have available, or how they will compare to the Galaxy, though, which may have a bearing on whether to go the Galaxy or the Caterpillar route.