Lots of room for judgement with such a rule.
That's exactly the point. Most of the posts in this thread are questioning the FO judgement. Yet if the FO has weak character or otherwise feels psychology inhibited from performing an action moving that decision making point to another location on the causal chain doesn't help him. The problem is not
where the decision making should take place the problem is
whether the FO should feel empowered to make the decision. Giving more room for judgement to a psychologically inhibited pilot isn't going to make him more decisive but less decisive because of the additional mental room he has to find excuses to do nothing.
The question here is age-old: what is the proper steepness of the command gradient between Captain and FO and when, if ever, can the FO violate that gradient? If there were easy or simple answers to that question they'd have been figured out and implemented by now.
At the end of the day there is one easy proposal to prevent every airline accident--everyone stay home. Once one accepts that this isn't a realistic solution then it simply becomes a question of trade-offs and risk management. Good luck trying to convince the industry that every time there is nervous Nellie as PM that a go-around is required.
