The common thread I seem to see in all the proposals is that creators are struggling with marketing and nay-sayers (those who ask why a proposal must be re-initiated for the ump-tenth time when prior efforts have failed) seem to think that the Area51 population is static.
I believe there needs to be specific tools for marketing and planning a proposal. Some people will be content with creating the proposal and seeing if the mud sticks. Others will want to rally the users of their group.
Being able to address the followers through poles, questions that are "proposal only" so they don't pollute the larger "discussion zone", and being able to form groups within the proposal to divy up work, I believe, would go far in allowing someone to manage a proposal successfully.
There should be more to building a proposal than just hoping that Area51 users will find it interesting....