well this is the only explanation since BA wasn't as inactive as before. Although, gst is coming up next month people are still not gsing as active as they suppose to be yet, because it's a bit early. In-fact a lot of people are still struggling on the quests and the number that is doing bounties right now isn't the same number of people that used to do pyrat daily quest.
Of course the castle update is amazing but I mean people barely spars now.
as flugore said hopefully the 'guild system update' will make the situation better.