Eh, I dunno, depends on the MOC and where it is. Something like...Axxon, gets away with open ball-joints pretty fine. But something like...the 2015 masters, they have a bit harder of a time. Open sockets are not too distracting on certain MOCs, but Storm beast shows us how to do it wrong.
Overall, I would have to say that Ball joints are far worse, but can be fixed sometimes (like the Masters....)