One small point: Diaspora currently uses Entypo for icons, and a decision was taken not to move to FontAwesome.
The first stage would seem to be conceptual: what Diaspora is for, and what sort of experience we want people to (be able to) have. From this design ideas will come.
Although it would be good to have a common strand running between the various elements of the project (Diaspora itself, the project site and the wiki) I don’t think the design needs to be completely unified throughout. As long as there is a common ‘feel’, that is enough.
We can use the minimal amount of branding necessary for users to know that they are using parts of one project. We’re not a commercial operation needing to ram home the branding at every opportunity.
If we’re going to change the design of the UI in Diaspora itself (and no reason we shouldn’t), we should allow users to keep the current ‘classic’ design if they want to. I don’t think we should force a change on people unless they want it.
I absolutely agree with your points about (a) accessibility and (b) responsiveness. Ideally, Diaspora should be equally easy to use for people with all levels of (dis)ability and on all devices.
If the Diaspora UI can be made completely responsive, it might be that the mobile version will no longer be needed. But that decision should be made as part of a separate discussion.
It looks as though you’ve made some decisions already (e.g. ‘Foundation will have a warm color palette suitable for discovery’), and it would be good to have some discussion about these things, but your input about them will be valuable.
It would be good to work out a minimum set of criteria for compliance with Diaspora’s design and branding, so that pods which want to customise their look can do so while still recognisably remaining part of the Diaspora ecosystem. I think this is what you address at the end of your proposal. Customisation of the UI of individual pods should, I think, be welcomed and encouraged.
Thanks again for all your valuable work on this.