The current configuration is a carrier yes, but for it to be able to go on a rescue mission I'd need to move the nacelles upward so that the Rescue pods (instead of the current Carrier pods) are more close to the ground, which would enable a ramp to slide down from the bottom and load people (or unload squads of soldiers...) to board the ship en masse.
But I'm glad you folks like it
I think the idea of an amphibious combat ship, in this case an aerospace orbit breaker, sounds far more interesting. No one has done one for Trek, and surface based combat concepts for Star Trek are rare as hen's teeth. It also works better with the idea of double decker hangar pods.
The issue I have with the pods is that they have an extremely narrow landing entrance, like threading a needle. It is made worse by the top deck creating a perfect place to ram a shuttle. It would be natural to aim for the middle of the opening but it is taken up by a knife's edge of deck. I think the new Galactica is closer to ideal because it has a single deck with a high entrance but even it strikes me as a dangerous looking approach.
One way around the issue is to open the aft portion of the top landing deck to increase options for landing. Or, extend the top deck outside the hangar tube. Also, if the ship lands, then the lower deck can be dedicated to surface equipment, while the top is dedicated to flying equipment. However, keep in mind that in TOS anti-gravity seems a little more common than even in later Trek. We would never see wheels back then. That ground based stuff would definitely be flight capable.
And as for all of you Nimbus lovers... Here you go

Something tells me those triple phaser banks should do the trick. As such I removed the rim's outermost phaserbanks; it proved to be a bit overkill. Still not sure what to do with the torpedotubes and underside of the saucer as far as phaserbanks are concerned though...
I was getting intense deja vu, now I know why. I made a TMP era
Starfleet Battleship ages ago, never finished, but it has quadruple phaser banks. It also uses the Meranda's hull as a saucer, plus the Enterprise's tail hangar, so it has copious shuttle space.
May I recommend Kelvan style torpedo turrets and moving the phaser banks back, to a steeper surface, so they can depress a bit further? I'm not a fan of the term Dreadnaught for any old super battleship but it also invokes a sense that the ship should be over the top in armament, like the Vengeance. Unless the deflectors are also graviton cannons I don't really see the crazy weapon aspect yet.
Over all, I love the design and how it is developing. It is unique, which on its own is worth while, but outside that it has lots of interesting things. It is also obviously a fun design rather than going for "Starfleet would definitely build it this way!" That's something I can support.