@tao@mathstodon.xyz who is going to award this priority? What is the incentive to slow down the process, rather than speeding it up as arXiv did? Currently I don't see really any academic incentives for expository work in math. You can think for example of Perelman's sketch of the proof of the Poincare conjecture, which he did not present publicly or explain in detail. And when Cao and Zhu wrote an expository article on it, they got accused of trying to take credit for it. And certainly they didn't get the Millennium prize for it - would the prize go to the explainer? This seems to fly in the face of mathematical practice.