I think IDT could be ignored if the starchild was removed. Hell, it would have been a better ending if we NEVER discovered why the reapers, well, reaped. Leave Harbinger as the big bad, his motives so far above our own understanding that we never know the how and why of the reapers.
That way, you can then explain the crucible (somehow...) and the space magic (somehow...) and finish the game with shep giving her life to defeat them, and no one ever knowing why they came.
That would still have left questions, but people would have been coming up with interesting reasons for the reapers existance instead of the garbage spouted by the glowing shit.
That way, you can then explain the crucible (somehow...) and the space magic (somehow...) and finish the game with shep giving her life to defeat them, and no one ever knowing why they came.
That would still have left questions, but people would have been coming up with interesting reasons for the reapers existance instead of the garbage spouted by the glowing shit.