"Carrying the team" certainly seems risky, and calls to mind the endless problems of Microsoft's stack ranking (especially the fights to get on a team with losers to "fund your raise").

I do think that the self-directed criterion is an excellent one, though. With that standard, you could promote an entire team if they're doing good work, or have non-senior engineers stretching up into your top decile. That makes the 'senior' title a clear assertion of "can handle these tasks without substantial oversight".