To me, if you have an architect on your team, their role should be

 

• To act as an unofficial leader in the team that mentors and teaches people on the team about architecture
• To make themselves unneeded - that their knowledge is spread enough so that they are no longer a bottleneck

 

A bottleneck? Yes.

An architect, by definition, is a bottleneck. If people need to come to the architect with questions that only the architect can decide on, then they are easily a bottleneck people are waiting on to deliver things. 

But an architect can be so much more than just "dispenser of architecture guidance". An architect should be treated as having something missing in the team. That something is knowledge.

Your team can't really be self-organizing if it needs to approach the company architect to make decisions. In that case your team is either in chaos or in learning mode. The architect can play a big role in making sure the team comes into learning more, by making time for the team to learn about architecture, and learn how to make important decisions about architecture.

The architect can coach and mentor each person on the team individually, and train the team as a group, to think about the architecture aspect that the architect knows so much about.

An architect should be thinking "why is there an architect role here, anyway?" and then make it their job to make sure that everyone is an architect.

When the architect is no longer the bottleneck, he can start learning new skills beyond architecture, just like any other member on the team. That's because an architect who's no longer THE architect, is simply a team member.

If there is a shared architect, their job is to make sure the various teams don't need him to solve their own problems. When his/her job is done, he can start propelling his/her skills in new directions, because he/she will have lots more free time on their hands.

An architect that does his job creates knowledge that is shared in the company DNA, and facilitates continued thinking and challenging ways to think about the same problems. Another option when he's no longer a bottleneck, is to dedicate him/herself to a new target and learning.

An architect is a leader in a specific area. A leader mentors and teaches other to become better, so that the leader is no longer needed for the team to organize. Just to set goals and constraints.

But an architect is just a version of a SPECIALIST.

Indeed, any any specialist in the company should be treated as a hidden leader. Every specialist should be mentored and challenged to become an unofficial leader that challenges and pushes others to learn about their specialty, to share in the specialist's knowledge, so that he's no longer a specialist, just a mentor setting overall goals and constraints about a specific subject.