I tried to clarify in my top comment that I wasn't saying we should avoid having experienced people on a team, but based on your response, maybe a little more c

I tried to clarify in my top comment that I wasn't saying we should avoid having experienced people on a team, but based on your response, maybe a little more clarification is needed. When I think about a "hero" in terms of team dynamics, it's a person who is consistently relied upon to save everybody else's butt, often by doing things that are flashy but not particularly healthy, such as working long into the night to meet an unrealistic deadline. When you have this sort of Superman figure who's willing to swoop in and save the day, the problem isn't so much their level of experience but the unhealthy level of dependency that's placed on their shoulders. I'm all for having highly skilled, highly experienced engineers who are productive themselves and can further increase productivity by helping unblock others on their team. And I agree with you that replacing them with some number of juniors without the same institutional knowledge can be disastrous. But if your team becomes so dependent on heroics that they can't stay afloat otherwise, then when that hero gets hit by a bus or just quits to take a position elsewhere, you're screwed.