I don't particularly think it's either, He's a man whose outright devoted and enthusiastic towards the things that he and his team create.
sure he over-steps the mark with his promises, which I think he's honestly toned down, but I wouldn't be too interested in buy a game that the CEO of the devlopers had little to no faith in.
His games aren't outright terrible they're just not exactly what he says they are, because he has a genuine vision of where he wants to take things with gaming and I highly doubt that even he feels that any one of his latest titles is anything more than a step towards that goal.
Like I said he just gets a little too enthusiastic about it, which is perfectly understandable. If I were to invest time, money and attention into a project I completely believed was worth the effort, I wouldn't turn around and say "You'll have fun with it, but it won't exactly change your life, buy Gears of War instead."
And that's my take.