Interesting, I just looked at a Victory itinerary for Feb 2010. it has dropped Antigua for St. Maarten. Regardless of issues with taxi cabs I would support that switch, thought I'd rather swap St. Kitt's for St. Maarten.
About 18 months ago they switched the southern itinerary from stopping at St. Maarten to St. Lucia. I think because it is such a long haul to and from Barbados. When we did that cruise it felt like the captain was giving it all he could on those two nights.