Hi Willi. Thank you for your message. All your questions are good and very relevant — I just disagree we need a centralised role to deal with them. In several companies I worked with, the ScrumMasters (or /Team/ Agile Coaches) were gathering together continuously to talk+resolve+propose organisational issues — they were also talking to the line management to propose+execute an agenda for agility. If it's not possible in your current client, well…maybe now we have a case for a "temporary" /Facilitator/ Agile Coach to facilitate this to happen.
If you have the chance please take a look on my book "How Creative Workers Learn" to get more on facilitating emergent learning.
Abraço!