First of all, I do agree with your starting assessment that Iran's foreign policy has not fundamentally changed, before and after the JCPOA, so I think at that level we are in agreement.
I would make a side point that I find—and this has been one of my big areas of research—that critics of Iran, to put them into a very broad category, tend to exaggerate the extent of Iran's influence in the region. Iran has extremely limited influence in Bahrain. Its support for some opposition factions is very limited and doesn't make a difference on the ground. It's the same thing for Yemen. The Houthis are not proxies of Iran. The Houthis are not puppets of Iran. Iran has a very limited influence in Yemen.
Other elements you mentioned I would agree with, but I did want to make that point.
I would disagree with the conclusion that reopening the embassy in Iran is making things easier for Iran, which is the way you phrased it. I think that's a mis-characterization of diplomacy, to be perfectly blunt. The point of diplomacy is to try to promote our own interests. We do have interests in Iran. We have consular interests. There are trade interests in Iran, and there are other reasons to be there. I don't think that by simply shunning them we can advance these interests. Having an embassy in Iran, having a limited trade.... We are never going to have big trade relations with Iran, not just for political reasons. They are far; we are far. We're not a big economy, so let's keep that in mind.
We are not advancing these interests just by taking the moral high ground.