Self Improvement in a team

What is the correct responsibility of the team to improve the skills of each team member? 

As in many businesses, Microsoft has a formal process for employee annual review, including a six-month "check up" called a "Mid year career discussion" or MYCD.   We just finished the MYCD process for most folks.

It is a time for introspection.  It is a time to address the stuff you truly screw up in.  A good manager points out the bad things you do and honestly offers to help you improve.

I think back to the time that I spent as a manager.  As painful as 'review' is for the employee, it is truly tough for the manager because of not only the time involved, but also the energy and effort it takes to go through your team, examine everyone's strengths and weaknesses, and dedicate yourself to the success of others. 

The fly-in-the-ointment is that the manager may not be qualified or capable of offering any good advice or resources to help address the needs of one or more employees.  We look to the manager to be an expert in career advice, and that's silly.  (It's one reason that I stopped being a manager.) 

In my current role, I have no direct reports.  I have a team that I collaborate with. 

When I look at the team that I work with, the people are a varied lot.  "You get them as they come" is a good way to put it.  Some more skilled than others, usually in completely different ways.  It leads me to ask: what is the correct responsibility of the team to improve the skills of each team member?

More importantly, can the team be the place where an employee can get the support, mentoring, and reflection that they need to improve themselves?  Can a set of messages be equitably and fairly conveyed to allow team members to support each other in key ways, to make the entire team more successful?

I have questions today.  No answers.  But I think there is something worth investigating there.