Finally, guessing what a Calvinist would or would not like to see added to the Gospel is not helpful. I don't want to tamper with the Gospel. Those I know don't want to tamper with the Gospel. All true Christians don't want to tamper with the Gospel. So please, limit your beliefs about what Calvinists want and don't want to what they profess they want and don't want.
I sense you are a warm-hearted Christian who would shy away from giving the Calvinist construct the pride of place given it by some of your fellows, so don't take offense.
Here's how Calvinism is vicious. Christ spent His earthly ministry inviting all He encountered (in an undifferentiating way -- so far as we can tell from the Gospel accounts) and castigating ONLY those who refused. Moreover, He singled out on several occasions a apecial status for 'little ones' -- innocent children. I take those as contextual truths.
Now along comes the construct and it neatly consigns the vast majority humanity to Hell (from the foundation of the world) without any opportunity to choose and including large numbers of children and even infants who never heard the Gospel.
Now, that, my friend, is a viciousness inconsistent with Christ and inconsistent with His express teaching. Were it otherwise, He would have threatened with a worse-than-millstone future those who hindered "only those of all these little ones who are predestined from the foundation of the world to be saved." And, BTW, such a statement would be deprived of meaning in any event since (if the Calvinist construct were true) there would be nothing His hearers could do to "hinder" the little children anyway.
The Calvinist construct is, in short, just that; a nifty little theological construct overlaid over the Gospel in an effort to answer a few questions we don't need to answer. But in doing so it turns the Gospel of Christ into something we cannot recognize -- a prideful, vicious, exclusive little club -- and the Saviour of Mankind into a befuddled prophet making pronouncements to all which He knows don't apply beyond a few.
You will pardon me, but I will take the Christ of the Gospels and the New Testament, not the Christ of the Calvinist construct. God bless.