Currently the TCG only mentions Tech Ambassadors in the context of translations. While there is a connection between Tech Ambassadors and volunteer translators indeed, they are not exactly the same concepts. Tech Ambassadors have a (mostly untapped) potential for mediaing in the participation of communities in product development. For what I know, this was in fact part of the original plan. We have a mostly non-publicized mailing list and it is already being useful, but with some (little?) extra effort we could have a lot more.
Topic on Talk:Technical Collaboration Guidance/Milestone communication
Affirming that "what do we do with tech ambassadors?" is still an open question, up to and including "who is 'we'". I do think this has a part in systemic community engagement, but I think creating, executing, and then maintaining a plan here is a pretty big undertaking since, at the end of the day, it's volunteer management. It'll take a dedicated project to revamp the program, IMO.
Volunteer management is one of the specializations of the Technical Collaboration team. Instead of revamping, we could do progressive improvements, planning one per quarter or so. What is important is to agree on an objective first. We (you, I) could ask in the tech-ambassadors list, pointing them to this thread.