I don't agree at all. Prophets were referred to as "son of man" as well throughout the OT. Further, I see no claim that Jesus claimed to be the Son of Man in Daniel. Daniel was apparently referred to as the son of man in Dan 8:17. Daniel also speaks of one like the Son of Man.
Jesus was not convicted for being the Son of Man, but for claiming to be the Son of God.
Matt 26:63 But Jesus held his peace. And the high priest answered and said unto him, I adjure thee by the living God, that thou tell us whether thou be the Christ, the Son of God.
64 Jesus saith unto him, Thou hast said: [Christ did not deny it. This was the "blasphemy"] nevertheless I say unto you, Hereafter shall ye see the Son of man sitting on the right hand of power, and coming in the clouds of heaven.
65 Then the high priest rent his clothes, saying, He hath spoken blasphemy; what further need have we of witnesses? behold, now ye have heard his blasphemy.