I think it is incomplete in some ways, while getting the main things right.
That common ground between us should be enough, but obviously something else gets in between us and so we fight about it.
That we fight about it gives me very strong suspicions about the identity of the real agent who is encouraging our misunderstandings, accusations and the battles that result.
None of that is coming from the One we Christians all agree we follow. That's not His stuff. Nope, that's the enemy's trademarked style and verified by the results.
We have far more to agree about than fight about, and if our egos could be silenced long enough for us to hear what God has to say so softly, we'd stop ourselves.
I think not. Read Jesus words to the seven churches recorded in Revelation. He didn't focus on the "things they agreed on" but addressed the areas they had strayed. This "things we have in common" appeal is bogus.