Many interesting views on this subject. In my outfit, I'm a relatively experienced F/O and I've happened across similar situations but seen from the other side (flat cockpit power gradients). The worst situation was with a new DEC who had virtually no experience on type and furthermore had no experience of our type of operation (Scheduled pax service). It was allways his call, but in those situations it's difficult (if not impossible) for the F/O to just stand by and watch as mistake after mistake happens. I would never dream of telling him that it was my plane on my PF legs, but it's also very difficult to take critique from someone who has so much less insight into the operation. He probably percieved me much the same way as the original poster percieved his F/O, although I'm quite sure that in my case, experience levels were more extreme and affected the situation to a greater extent and in a different way from the original post.
Many posters seem to note that the cockpit environment has seen a change over the last couple of years. Coupled with comments regarding recruitment processes and filtering out the bad seeds, I can't help thinking about the "pay for your job scheme". Today, anybody with money can buy his/her own type rating and get a job. This has also been very clear in my outfit as we have had virtually no recruitment process whatsoever. As long as the applicant has had the correct type on his license, he/she has been welcomed aboard and this has resulted in more than one situation where crewmembers judgement has been in question. As long as this trend continues, these issues in which poor CRM is the main factor, this trend in our cockpits will continue.
/LnS