Sorry my first interaction in such a long time is in opposition to a point you made. Over decades, I have found that many of my Reformed friends are too quick to call “heresy.”
I suppose the first point in any post discussing heresy is to note how problematic any working definition of that term is. I suspect that you know that almost all (and probably flat “ALL”) Protestants are heretics even under definitions that some of us accept. (Huh? Well, some of us accept those definitions without thinking through the implications.) Second, even those Protestant—but let’s cut to the chase and talk about “Reformed”—theologians who are smarter than that, e.g., R.C. and R.C., Jr., have struggled to fashion a working definition.
Be all that as it may, even Reformed theologians with outstanding credentials assert that Arminians are not heretics. Besides R.C. and R. C., Jr. (who sometimes seem to be trying to have it both ways), here
is just one example. Here is a man with significant credentials—although with those credentials, he ought to understand the view he is opposing MUCH, MUCH more accurately—who declines to call Arminians heretics, EVEN with such false views as he ascribes to them. Fortunately, he understands the concept of heresy and declines to ascribe it to Arminians.
I write this about Arminians because I have read some of the key primary sources. I have not done so with Molinism, so I will not pass judgment. I will say however, that having read multiple, not just con-, but also pro-, secondary sources; I have serious reservations about it.
By the way, I am always perplexed that my Reformed friends (at least those who are well-informed about the theological label they claim) are so quick to call “heresy,” when so much of their own system is made up out of whole cloth—a point I made earlier in this thread. Looking at the first 2 Sproul videos that you recommended, I was glad to see that he admitted that the Bible doesn’t directly support the Covenant of Redemption. (And he mentioned in passing the doctrine of “probation.” I assume he would also admit that the Bible does not directly support this doctrine, since he seems willing to be truthful about doctrine origins.) Unfortunately, Sproul claimed that the Covenant of Redemption is based on “inference” from the Bible. That stretches the meaning of “inference” WAY beyond any normal or (in my opinion, legitimate) meaning.
It may be that he explained “covenant” better in later videos, but if he did; I’d be really interested to see what he claims the SIGN of the redemptive covenant is and what the CEREMONY of the redemptive covenant looked like. I can't even imagine these things happening within the Godhead. Of course (since it would all be speculation), nothing can be found about this in the early Covenant theologians--of any stripe. In my view, the Covenant of Redemption, the doctrine of probation, and much more of covenant theology is made up out of whole cloth. If I am correct about any of this, it seems awfully chutzpah-y to accuse Arminians of heresy, as so many of Reformed folks do.
By the way, I am not—as you may remember—(completely) an Arminian, and I am not (at all) a Dispensationalist, if that makes you feel better. Obviously, I reject the view of 5-point Calvinists (as opposed to 4-point and 4 ½-point Calvinists) and their Armenian counterparts that it is “all or nothing.”