It is very easy, in a capacity as an authoritative teacher in the Church, to come close to or even cross lines into wrong teaching, which is what heresy is.
There are legitimate criticisms, and they must be assessed in degree. Not everything is black and white. Shmemann is flat-out a model of gratitude, the key to joy, for us. Hopko is a model of speaking to modern pluralist Americans who swallow truths more easily if they think the speaker doesn't sound dogmatically sure of them. (His mannerisms ("I don't know", "It seems to me", etc when speaking about definitive dogma) drive me crazy, but I get their effectiveness in the environment we live in today.)
It is possible to go too far in something. And usually, in my experience, it is in the direction of one of two equal and opposite errors. A person can, for example, say that "only Orthodox can be saved". Or they can take the opposite tack of ecumenism and say that it doesn't matter whether you are in the Orthodox Church or not.
Or they might teach that every word in the Bible has to be taken literally, that there is no metaphor or allegory, or the opposite error of saying that many or most miraculous events described are only metaphor or allegory.
Hopko was a thoroughgoing evolutionist. He believed that modern science, a result of modern education, produces truth about our origins that must be reconciled with patristic teaching, even to the point of belittling the latter. I still hope to write a criticism of his podcast on "the Slippery Slope", in which he was right about the specific case he defended, and wrong in denying and deriding the concept in general.
Shmemann was an ecumenist. He did believe in the Orthodox Church, but swung too far in the direction of "it doesn't matter".
Heck, I even found hints in Met Antony Bloom that he might have supported women's ordination, and more than hints in Met Kallistos Ware.
Such tend to be linchpins for "liberal" folk in the Church, and while they themselves did/do not teach such things as teachers like Fr Robert Arida have been trying to introduce (the legitimacy of homosexuality in the Church), their tendencies were influential in such directions.
I would stress the vital role Shmemann played in revitalizing the Orthodox Church in America, of turning it from a moribund club of isolationist immigrants to a thing that reaches out to Americans and fulfills "the Great Commission", and Hopko's continuation of that, combined with his down-to-earth relatability that Americans so desperately need, and let's face it, we really couldn't perceive Shmemann as American.
So there's no simple verdict. But overall, there is definitely much more good than bad, but you need to understand that they were "only human", and what exactly they went wrong in, even while being incredibly and deeply right about so many other things.
