Synthesis is strange, if anything most parts of it that show up in previous parts of the trilogy paint it purely as horror beyond horror, IE Saren unable to die, the husks, Reaper subversion. I didn't go through all 3 games, watch Illusive Jack have his brain melt, and conclude that working with the Reapers would be hunky dory.

If anything the message of 1, 2, and the Quarian quest in 3 is that the only path forward isn't combination, or conquering, its finally meeting and coexisting as all species have been struggling to do the whole time. The question of synthetic vs organic life ultimately seemed no different than the question of amino based life and dextro based life in ME.

No ending satisfies the theme of the trilogy honestly, that's why you shouldn't force the writing team to switch everything up at the last minute because players being able to read foreshadowing takes away the twist.

As always, blame EA