I have always thought that the aftermath of the Romulan Wars and building of the Federation is what the pre-TOS show should've been about. DS9 had just had a war but ended before they could get into the hard work of the recovery and rebuilding that comes afterwards, which this show would've been about, so they would look at a new crew having to work together with a mixture of human and aliens onboard one ship to help foster better relations and understanding--which would of course cause issues over time, whilst each of the crew would have to deal with all that they had gone through during the conflict, all whilst trying to carry out a somewhat political/PR mission of exploration, to show the civilians out there that though their alliance was formed during wartime that it has many benefits.