It seems to be something of an unspoken rule of superhero movies that performances of gritty characters require some sort of vocal gruffness to match them. After all, Batman, Bane, Hulk and Thanos would sound silly with a voice like David Beckham, wouldn't they?
Still, in a film so concerned with meta-awareness, to have Josh Brolin's Cable arrive sounding so cliched and like he's been paying a little too much attention to Batman movies recently is slightly jarring. There's no way he should be able to get away with that.
As long as it's played self-consciously - with Deadpool at least referencing the fact that he's doing a full Christian Bale Batman growl at times - then it'll get a pass, but for now, it's a bit much.