Center cockpit monohulls don't have to be big, Nor'sea 27 comes in aft and center cockpit configurations. The center cockpit has a little aft cabin berth, and it appears to be more enclosed, or "contained" in the cockpit. It might actually improve your safety to be in a tight little cockpit in any stink weather, rather than exposed from the stern. You also would work the boat from a central location.
On small boats though, an aft cockpit would give you more cabin room, rather than having two small, split up cabins. Imagine having to leave that neat little aft cabin to climb through the cockpit just to get to the head. This of course wouldn't be the case on bigger boats, but I'm talking about this boat in particular.