The Retaliator as a bomber never interested me much, which is why I never bought one until it went modular despite loving its design. The Retaliator as a drop ship though? Hard to beat that one. Twelve marines and an armory on a drop lift in the front. Cargo hold with Titan armor suits, or perhaps some future combat rover on the lift in the back. Combined with the turrets covering pretty much any angle to give support during insertion/extraction, and it seems like it's practically made for the job. Sure it doesn't have super shielding or anything so it will need escorts to keep fighters off it, but it's more than enough to deal with whatever pea shooters ground troops would have.
As for the Starfarer, I disagree with it being able to do a bit of everything. It'll carry cargo, process fuel, and that's about it. The thing is going to be a massive pig, so while it has decent weaponry, it's more to to act as a deterrent and help when shit hits the fan. I highly doubt you'll want to bring it into a fight just for combat's sake. Nor is the ship going to be a good explorer. Perhaps an an accompaniment to a Carrack for range extension, but not by itself. It's lacking the necessary tools for the job. Needless to say you're not going to be racing, mining, salvaging, repairing, boarding, etc with it either. Modules might be able to skew it a bit more in a given direction, but as it stands now, it's rather limited in scope.
Generally speaking, the bigger the ship, the more specialized they become. They do one thing damn good and perhaps can pinch hit at one other field, but they're not really multi role ships. The only exceptions are the ones like the Endeavor where the ship is meant to be a blank box that you define.