We've seen plenty of examples this year of what happens when the first receiver gets sloppy service from the dummy-half - the defence are up in his face before he has a chance to do anything. Granville is actually a very good passer from hooker, he gives JT, Morgan and Coote a hell of a lot of time to work with. Peter Wallace last night was another good one to watch - very skilled at the scoop and pass in one motion pickup, to either side. But then, he's a half who grew up in an era where you didn't play 'corridors' quite so much, so he's had plenty of practice at sending the attack either way even as a halfback.
If the hooker isn't required to give the first receiver quick, clean ball - then who is?! Just because a hooker is good at scooting out and taking a run himself, or is a decent kicker, doesn't mean he hasn't got the basic passing skills down pat either. You might notice the explosive runs etc more, but 80-90% of the time (in attack), it's fast, reliable passing to the first receiver they're there for.
Which is why the 'running interchange hooker' is used by a lot of teams for quick spurts here and there - you can afford to drop off the reliable service to the first receiver in little bursts and gain an extra ball-player to change it up, but if you wanted your hooker doing all the ball-playing, he'd be your halfback or 5/8, not the hooker to begin with!
