Sorry but I have to more than disagree.
The staff members may play gamemodes they please. But, some of them have priorities. For example, we may have a staff members that also a builder so they spend a majority of their time building in creative and moderating chat, etc. I tend to be doing details and little things in hub with result me being AFK there, I go on forums whilst I'm moderating the hub.
Periodically I may issue a staff member to moderate a specific server due to the fact there may be a increase in rule breakers. We currently don't have much staff moderating gamemodes, but I am working on that.
I do see your concern and I will try my hardest to get staff members up and running once again. (It is the weekend so I should see more on *cough*)