You can't expect multiple passengers to be simultaneously removing seats from their housing to facilitate their escape. That would be hard enough if it was warm, dry, the right way up and well lit. But it won't be, it'll be the opposite. They really need to address this with a seat re-design before tragedy strikes.
But how often are there going to be multiple passengers over the sea? As with the Sea King, the S-92s will spend most of their time with 4 crew on board and 1, maybe 2, casualties. And those casualties are rarely in a fit state to escape a ditching, however good the emergency exits are. The most common time that a SAR helicopter is full of pax (or should I say, non-aircrew folk) is when deploying MRT, which doesn't tend to happen over the water. Of course there are very occasional rig evacuations/whole ship's crew pick-ups, but these are the exception, not the norm - in stark contrast to the oil and gas aircraft. Does this mean that emergency exits being obstructed is ideal? Not at all, but let's not pretend this is a daily risk for the future SAR crews and their passengers.