They are literally toned down BECAUSE they’re too useful in combat. I believe it was the season 9 DVD (or was it season 8?) where Misha Collins himself addresses *exactly this*, by reviewing that Cas is in concept too OP and that’s why the authors nerf him in various ways and he understands that, because it’s HOW they manage to keep Cas around and keep him relevant without being able to Deus Ex Boopica all their problems away.
He’s already nerfed as an angel, I see no reason whatsoever to hold onto any of that when the point itself is that he can be useful and complete without them.
reblogging for “Deus Ex Boopica”