I don't understand people not rating Trossard, I think he was great last season. I think we'd notice the whole he left if got injured or sold.
He is excellent now and then, just too rarely. I agree he would be missed though as there is no similar player in the squad who could fill the void. After all, when he does have a good day he is usually the main reason for the point/three points.
Not giving up on him, a bit more consistency and no one would question him.