The Christian Science Monitor reports on the wave of teacher retirements in the Wisconsin with coverage of the MG district and an interview with retiring history teacher Tom Howe. MG has seen 17 teachers retire this year, considerably more than average.
I do think the article falls short on a couple of points:
1) It fails to explain why many teachers are retiring this year: Teachers eligible for retirement are doing so for guaranteed access to retirement benefits that are part of existing contracts, these benefits will be at the sole discretion of school boards in the future.
2) The recent changes to WI law will result over the next several years in less turnover of senior teachers, not more, even including the increased retirements this year. The reduced pay and retirement packages will have teachers working longer before retiring. This will result in actually slowing the "changing of the guard" that the article identifies as a silver lining.
3) I think the idea that replacing senior teachers with new teachers might improve student outcomes is speculative and unproven. While it may be true that younger teachers have attitudes more aligned with current school reform efforts, this isn't necessarily better than experience. In fact we know there is a positive correlation between the level of teacher experience and student achievement.
It should be noted that early retirement benefits were initially introduced to save districts money by encouraging senior teachers at the top of the pay scale to retire. The explosive growth of health care costs, the major early retirement benefit, has significantly changed this equation, although I estimate we still at least break even.