I take it you've never seen Kovalchuk play? One of the only players where you cannot leave him alone at the blueline on a PP. Brett Hull had a wicked one-timer. I mean, there's only so much you can do with a wrist shot from farther out.
I would argue that a quicker release is more important than speed.
As to disguising your shot, if you release quickly, then there is really no disguising it. Although, and maybe this is me believing this many years ago, but why do players use white tape if you want to disguise your shot? Tippett has alternated between white and black tape during his career, which I find interesting.