The only thing that surprises me here is that you say there was footage showing a spider-shape-shifted Druid walking freely among spiders. I watched the PFH2, but while doing something else at the same time (more exciting than watching Swen bore people, I confess), so I most certainly missed stuff past the first 30 minutes.
What doesn't surprise me is that the spiders attacked you.
Previously, with a ranger, I called a "familiar" raven, and went on to scout the map with the raven. Upon entering the Blighted Village, the ambush goblins attacked my innocent bird.
I got the impression that, when they see a raven (or cat, or else), enemy creatures in the game know that it belongs to your team, and so they attack. While in all credibility, they should just ignore it. In fact, exploring freely without raising suspicions is part of the basic usages of shapeshifting into a bird (or cat or otherwise weak creature that you wouldn't shape-shift into for combat).
Needless to say, if that's confirmed, I'd find this pretty disappointing and hope that Larian changes this.