ok we all know about the shoulder problems with dynamic cloth and conforming cloth.i think the problem is the T pose from M4.

 

this is how it looks.

 

if you look at jackets or shirts you see that the sleeves are not in that kind of pose. so what happens? when you bend the shoulder the cloth streches to much.if you think about it the shoulder and trapez are one part. so it looks strange.

 

my advice is to pose M4 different and export him out and model the jacket,shirt,... in that pose. i got fantastic results with teh shoulder. it looks more realistic.

 

i will post some renders.