I've been debating this point myself. Part of me thinks he meant that he screwed with the spell sigil to push Sam into the background of his own mind and take full control. I mean if not, then the blue eye flash thing makes no sense. I doubt he'd do that for show. No angel has before. What plot points had you saying that Sam was acting a little off? I didn't spot those. Now I want to go back and watch to see if I can see what you did. I don't remember Gadreel saying Sam's been gone 'for a long time', just that he's 'long gone' and that he's been playing Sam convincingly. But again, not sure for how long he's insinuating. So many questions! lol