I think that a better date to track the beginnings of GNOME Shell would be to the 2008 GNOME UX Hackfest. I was there, and infact on the shell team that did the original mockups for what would become GNOME Shell eventually. It was discussed at the Boston Hackfest immediately after. Infact, by the time GUADEC came around it was already packaged for Ubuntu.
One of the things that was discussed as a principle at the original UX Hackfest discussing this was the simplification of the panel. Basic menus, not the notification area hell that had been created. It was widely agreed upon then. I would say that this is also the public origin of the work that would become libappindicator -- though I didn't have time to work on it until later.
At the last GNOME UX Hackfest at Canonical's offices I was not there. The big reason is that I felt that too many Canonical employees attending the hackfest would create a "mob" atmosphere since it was already in the Canonical offices. We decided that Canonical would just send the folks already in London as it was less travel costs, and already more than enough people. I asked Matthew Paul Thomas to discuss Application Indicators with John McCann also at the hackfest. I believe that they did have that discussion, and left with an understanding that AppIndicators aligned with many of the same design goals as Shell along with the fact that we were interested in what changes the Shell team was interested in to make it compatible.
This is infact a similar conversation that I had with John and Marriana at the 2009 GUADEC where we discussed the messaging menu and libindicate which is the application side of the messaging menu. I was concerned that we had asked application developers to support a new API, and that was a big ask, it would be good if no one (us or Shell) would have to ask that again. They said that they wanted to do a little more with the messaging aspects of Shell, but they weren't sure yet, so I left it as "we'd like to work together, tell me what changes we need." As I'd like to make changes so that we could all use the same library for messaging tasks.
So, in review, I most certainly know about GNOME Shell, and I still believe that libappindicator is a great GNOME 2 way to get to the design goals of GNOME Shell. Unfortunately the GNOME Shell team has decided that there is no longer alignment there. I haven't seen any rationale for that, or seen updated design documents that change things signficantly enough to say that the libappindicator methodology no longer aligns.