Part of the new program is an explicit focus on frequent feedback. If anything, there ought to be fewer surprises than the current once (twice-ish with midyear discussions) a year feedback.
The risk going forward is that without being forced to a distribution, wishy-washy managers will trend towards the middle. High achievers will be under-compensated, and under-achievers will be overcompensated. The budget hasn't changed, so the same pool of money has to be divided among the same set of people, managers now have more freedom as to how.
Managers found out this morning. It's possible he was part of a pilot program and had early knowledge, but I suspect it's a coincidence. If anything, having early knowledge would likely have kept him from writing that until after the new Microsoft program was announced.