You're right, this is hard. I think there are three things going on.
First, there are too many design forums to keep track of. Bugs,
Blueprints, Brainstorm, design.canonical.com, mailing list ...
information overflow!
Second, a mailing list is a terrible forum for design discussion. It's
slow, text-only, and append-only. For example, you can't easily
compile a table of proposed designs and the pros and cons of each.
Third, many Canonical designers come from companies where they have
dealt only with colleagues, not with contributors outside the company.
They're really smart people, but it's hard to learn new habits.
However, we have just started work on a project to improve this
situation -- to communicate more, and to help other designers make a
real difference to Ubuntu. We'll talk more about this next week.
Cheers
- --
mpt