Even though the ship has two hulls (engineering and primary), apparently the primary hull is incapable of separating, and acting as a lifeboat as was the intentions of Matt Jeffries.
The ship also does not appear to have any conventional lifeboats and instead just has shitloads of shuttlecraft which are used apparently as lifeboats.
The ship (due to the lack of a separating saucer or lifeboats, and instead requiring buttloads of shuttles) is apparently monstrous in size just looking at the shuttlebay. I think I also saw a size comparison of the new Enterprise with the USS Kelvin and it also reflected that the Kelvin was a very large vessel, and when in combination with the 800-man crew, in most likelyhood, is larger than the (original) Constitution-Class (Which as of 2265, 32 years after the Kelvin's destruction, was the largest class of ship in the Federation inventory)
The engineering-hull looks quite small in size (not to mention, it looks like the bridge would be in the way of the deflector field) compared to the primary hull.
The warp-engine looks gigantically oversized, and the back has a glowing blue exhaust even when not at warp (Considering the ship has regular impulse engines, the argument that this is an impulse engine is moot). Gene Roddenberry specifically said when he created Star Trek that he did *NOT* want to see flamin' rocket-like exhaust shooting out the back of the ship (granted he also said he wanted warp-engines in pairs but that view actually seems to have varied over time) something which has been maintained all the way up to Star Trek Nemesis (which in my opinion sucked)
The interior of the ship looks completely trashy and junky, particularly that gigantic elevator shaft that extends right down into the shuttlebay if I recall. In every Starfleet ship shown in Star Trek, even the NX-01 Enterprise did not look that crude, trashy and junky, nor did it have a long giant elevator shaft hanging down all the way into the shuttlebay like that. The turbolifts always seemed to be "behind doors" and you never actually saw the elevator shaft.
The point-defense cannons the ship has was never seen on any other Federation-Ship, and the sheer number of overall weapons was ludicrous for that timeframe.
While this isn't really a complaint, or a gripe about the Kelvin, I am wondering why the Kelvin didn't blow up after just one volley, or just one shot for that matter.
The Constitution Class vessel shown in TOS had been refitted two or three times from when it was first commissioned and was in most likelyhood fitted with far more powerful shields and weapons.
The Refit Enterprise in TMP, had substantially more powerful deflectors than the TOS Enterprise, and apparently it would seem that it's force-fields were several times more powerful than the K'Tinga's which themselves had more shielding and deflectors than the D-7's which were about rivalable to the Constitution-Class.
The Refit Enterprise first flew in 2272 or 2273, and Nero's ship, while not a fleet-vessel (Romulan in this case) would have most likely been around during the Dominion war, and during wars even transport ships are often fitted with guns, generally ones that can at least do a little bit of damage to defend themselves against hostiles. Considering Nero's ship was from 2387, 114 or 115 years after the Enterprise Refit (TMP), in which time, shields, and weapons technology has increased DRASTICALLY (Particularly during the dominion war and conflicts the Federation had with the Borg)
The difference in shielding capability and weapons capability the Kelvin would have had would have been virtually nonexistant compared to the Narada, and I'm just amazed the ship didn't get cut up in one volley...