Hugh, that's exactly my point. Don't look for an "aggressive bopper". Look for someone who can throw reliably. That's the hooker's key role. It can win and lose games. The rest is a bonus.
Hooker throwing can make a difference but it is not the be all and end all. They need to be useful at scrum time, strong at the breakdown attack support and clean out, and in their ball carries and tackling. If their throwing is a bit dodgy, provided they can effectively lift in the lineout others can throw for them. As @Lee Grant has pointed out, Pleash (usually prop) can throw reasonable accurately. Sandell has done similar at high school.
My observation over several years of monitoring the U20 Selections is that the Selectors have generally chosen aggressive boppers where they can, and not just for the #2 position. They have also seemed to prefer players who are regular Grade players over regular Colts players when there is a line call to be made. Perhaps it is a bit of a strength in numbers mentality, as well as respect being given to the opinions and selections of the various Directors of Rugby/Head Coaches around Clubland.
I like to see a good throw executed by a #2 but I think many selectors trade off a potential lost lineout (worst case outcome is contested possession to the bad guys) against a potential collapsed scrum (worst case - Yellow card and/or PK against), hence their preference for boppers over throwers.
Consider how long the Wobs and Tahs have stuck with TPN who has had plenty of lineout throwing yips over the years.
Returning to Italy, it will be very interesting to see Coach Thompson's response to this performance. I'm in @Lee Grants camp and think that we won't see the strongest 23 named for that game. I suspect that Thompson will start with a reasonably strong starting 15 with the dirt trackers getting named on the bench. It is critical that we get a 4 try BP victory against Italy.
Once we have scored the required 4 tries for the BP and victory looks more or less assured, I'd think that he would bench the stars and give the dirt trackers plenty of game time. This would reduce the risk of injury to the likely starters for the key game against the Saffers. That is the game we need to either win, or gain one or two Bonus Points from the loss and our rock stars need to be fresh and ready.
On that basis, I can see McInerney getting a fair bit of game time in the Italy match even though I think that he played a fair bit below par against the Samoans, but then I can't recall Fainga'a exactly setting the world on fire when he came on.