I have a 550. I don't think manual indexing slows me down that much. It is just part of the rhythm of things. I can easily crank out 300 rounds in an hour. I would like a case feeder, but I don't see adding one to the 550.If i have one i want to pull out and look at, I can. It moves when I move it. I have opportunity to pull the case at the 1st station, look at the primer. I have time to glance in the case and check the powder charge. Nothing moves til I move it. I don't know, I'd be lost if it moved on it's own.
Your thumb pushes the index bar, it aint a thing.