In the original timeline, Nero got his ship heavily modified with modified Borg technology, enough that the ship is somewhat alive and 4X its original size. Though I thoroughly agree that the ship should have had much more than missiles and the mining laser/drill.
what if it was the Nerada VS the Death Star? Nero would be 4x as fucked. and another, what if it was the Nerada VS 2 Eclipse Super Star Destroyers, 3 Imperial Super Star Destroyers, 4 Victory Classes, 5 Venators, and 6 heavy missile patrol ships? Nero would REALLY be fucked.