Majority of problems that you have listed happen with any company. Staining will happen when dyed clthing is put right next to the body. This was the case with Enterbay's Leon & his beanie as well as with Damtoys' Gansters kingdom Spade J Memories
As for bodies that have no articulated joints in the arm, don't be an idiot & pose the hell out of them, use your brains
PERS has nothing to do with disintegration over time. My DX09 pers brok an eye the second time I posed it. And if your two face/Harvey dent body is week, just get a new body!
If you are losing pieces, take better care of your items!
Oh, & my IM Mk. V still has RED panties, my first HT figures Dallas & Kane - are still in superb condition, which is all the more surprising as the whole spacesuit is made out of rubber
Yes, there have been mistakes - The comedian & Batsuit Begins come to mind because of the oil leaks, but that is unfortunately a side effect of using rubber. Without mistakes, how can you learn & improve?