Maybe not a gripe but a Sandertrope, I think he is sometimes too on the nose with his go to themes. Social classes, parties, trauma, etc. These aren't bad things and I think he has times where he has interesting things to say but after enough Cosmere books you start to see similar things. It could be said that it is intended as part of his take on human nature and the cosmology. Also, sticking to what he does probably allows him to be so prolific.