The 'good' description, along with excellent conition etc are always going to be vague depending on how you want to use them imo. I think loose is acceptable that one would believe it to be out of the box and if it were joints hopefully they's say loose joints.
I always give any toys I buy a clean. Never know whose grubby mits have been on it.
I often wonder what the point of M of MISB is there for really. If it is in sealed box, which we assume means never opened, then the toys should be mint. Many figures come from the factory boxed and aren't mint. Add to that MISB, could mean a perfect toy in a sealed box, since there is no clarification of who or when the box was sealed a re-sealed box could well be a fair call.
Perhaps we should start a motion to have MISB changed to Factory sealed/never opened?