We have put the place on the back burner for now for the reasons above. Many of my friends feel the same way.
I loved Beausoleil the first 2-3 times I went, but I went recently for lunch and was not as much impressed. I think the restaurant is still one of the best Baton Rouge has to offer (not that that's saying much), but I do know what you mean.
The lunch menu did not stand out to me nearly as much as the dinner one does.
Also, a couple times ago when I went, they were out of both pork cheek and mussels as well.
Give me sautéed yard work or something if you must be trendy. Steamed marigolds, caramelized wood shavings, whatever.