Here's a post at Information Dissemination from last week (and therefore refreshingly free of post-debate polemics) on the subject of fleet size. Main thrust is: Yes, it's true that killing power per ship has increased enormously, so one 2012 ship != one 1912 ship. But a large part of a navy's job is deterrence (i.e. convincing adversaries of the folly of conflict and the certainty of our response), and for that you need lots of ships.
In short, a thoughtful piece that makes no mention of horses or bayonets.