I'd see it more along the lines of having Earth like we have old style villages and historical sites. We don't live in those places, but it would be nice to visit and see where we came from. In this case, they'd just have to evict the current occupants and do a bit of 'restoration' to the planet.
But yes, those ships allied with the Federation would be wonderful. A 10 km long ship, from
here that can transpoort other ships inside, has faster speeds, and internal manufacturing and repair facilities? It'd be better than a starbase, let alone the Voth higher tech base for defense (go to DS9 and 'defend yourself' against the Dominion fleet).