Well, we do see Cap both in his Ultimate costume (which I hate) and in his classic costume with the real shield, so that's definitely going to get addressed. I also caught a glimpse of what looked like Cap breaking loose from somewhere.
Season 3 had me concerned but ended strong. Season 4... wow. Fantastic opening episode once again! I finally get to watch the show in HD, and it is really, really nice. Loved that the modified opening sequence tradition continued.