yes I do agree that shadow weapons are helpful but mid-grade would do the trick, When you added TOP-B (Shadow), the value of normal weapons decreased by 30% but it was still weapon needed for noblesse.
But when you added TOP-A(DINO) (Shadow) all A weapons dropped to the price of crystals i think 50%, these weapons have the same P.atk and SA as the S - Grade weapon
Summing up, I think that MID - B GRADE (SOV, Keshanberk ) and MID - A Grade (SOM,DLE, etc.) would be ok