What is it that makes you think that the Shema precludes a difference in roles? As understood, the Unity and Unicity of God is about His Being, His Essence, His Existence.
SD
Two separate points:
1) The trinity denies the Shema. The Shema, as well as numerous other OT verses, clearly define God as ONE. (And yes, i'm aware of how Christians interpret plurality in the OT God of Genesis. Even if i could go along with their plural interpretation,(by simply ignoring how Jews define their scripture...as well as all those other verses claiming God is ONE) it still doesn't say God is THREE. Why not four, five, six, seven or more? . Why just a trinity when God could be 2 in One, or 4 in One, or 7 in One, or 100 in One? All those combinations too could relate to His Unity, His being, His essence, His Existence.
2) "The son's role in relation to the father is clearly subserviant, NOT equal." I was referring the the New Testament here. Even though Nicene Christianity has made Jesus equal to God, the overwhelming evidence of the NT shows Jesus to be subserviant, not equal, to God the Father.