I really havent been on the other inner alphas as much as New Virginia, but proportionately there seems to be much more lag there.  Sure, more people are probably there than the others, but not so much to cause that much more lag, and regular periodic spikes of lag namely.

Coincidentally, New Virginia is the only (publicly known) island being monitored for the zone travel density map, which tracks player movement and displays a heat map of where people walk most often.  Here's the map.

So, might it be possible that the increased number of people running/skittering around the island, and the server trying to log this data, be causing the lag spikes?  It seems particularly suspect that you can actually see individual paths drawn on the map, so a lot of data seems to be collected for this, and not just a snapshot of player locations every few minutes or so.