I enjoyed this thread on naming.
My favorites are @resultBuilder for the reasons discussed in the thread and the simple @builder. Either are general terms which are specialized to what is actually being created: @ViewBuilder, @SlideBuilder, @BikeShedBuilder.
As to the rest of the proposal, I've been using @_functionBuilders since they were available and love the power they offer for simplifying APIs. I am not expert enough to understand many of the objections but hope that smarter people will adjust the proposal in accordance to those that will have impact.
I really appreciate the work and thought put into the proposal and the review. I think this is going to be a big deal.