Layout is still being tweaked and you want the UI to be as easy to manage as possible for people doing the AMA (new reddit is likely a factor in more recent AMAs not being as good)
It’s a bit of a chicken and egg situation regarding amount of people. More people will bring in more AMAs because it is largely a publicity thing. A low userbase means people may not want to do an AMA, or choose to do an AMA on a larger platform. But having AMAs brings people in. It’s hard to get the ball rolling.