A lot of the members of the team are inactive. (From what I've heard in the past)

So work tends to get pinned on the more active devs.

I kind of agree with you though, because I personally prefer some specific staff's styles and when a holiday's content is made mostly by one person who's style isn't really appealing (not to me anyway) it's a huge disappointment.

I love a lot of Sun's work though, especially the heads and bodies she's made.