I think this gets to one of the really interesting tensions in the bill. On the one hand, you could have just the local riding associations making the decision; on the other hand, the status quo at the moment, with the sign-off from party leaders. With the original bill I believe it was entirely one end of the spectrum, with it just going to the local riding associations. I think with moving towards a more enabling and prescriptive approach to the bill, it would be interesting to enable parties to make their own decisions.
I think there's potentially some interesting middle ground, for example, by having the local riding associations choose somebody regionally who can balance these interests, but also without it being entirely beholden to the party leaders. In that kind of situation they could say, “Actually, we don't think you're an appropriate candidate.” But also it would still leave room for local candidates, who perhaps have views that are different from the party essentially on some important substantive issues that are very relevant locally, to still be the candidate.
I personally would be interested in seeing a more prescriptive approach than just saying the party assigns one person.