I'm afraid I don't understand. I was really only disagreeing with the gear and loot for the content you're proposing in that quote, not the difficulty of the content. If you read my post, you'll see that, while I did say that the issue is really more in the fact that the content is not PUG-able, I did also say that they could make "midcore" content at least as hard as Coil was post-nerf.
The reason I suggested that specifically was because, while they certainly did require party coordination, it didn't have to be flawless. Without any party coordination whatsoever, what you'll end up with is something a little too similar to dungeons (which I agree are too easy). But why not give it the difficulty of, say, nerfed Rafflesia? Blighted Bouquet was more or less a guaranteed death if not handle properly, and due to other mechanics, a guaranteed wipe...pre-nerf. Post-nerf, however, people consistently ignored or mishandled Blighted Bouquet and the party could still recover.
EDIT: To clarify, there are points in your post that I did not address, such as tokens and respawn limitations. I did not address them not because I don't think that they are good ideas, but because I think there may be an easier solution to creating midcore content.