The lack of bracing strength has not been forgotten -- that is why it has an anchored mechanical mode, as well as why the mechanical mode has multiple such anchors instead of just two. While the illustrated one has only 4 anchors, it may be possible to put in 6, 8, etc. There is a strength limit in frictionless mode, so for lots of pushing power, melee combat, or heavy weapons with lots of recoil, the unit would have to switch to the mechanical mode.
It's hard for me to envision what you're asking to a degree, but I think I know what you're asking. I think you mean "Can you move the ball inside the socket without changing the alignment of the shaft", right? Well, while in theory a socket with lots of room could hold such a ball and do as you say, the metal shutter system which is used to protect the interior of the socket and the ball inside simply doesn't allow that. Such a system would require a very large opening for the socket, possibly larger than the ball, and it would need to be shielded somewhat differently.