...except that he'll have to wait an additional year to transition, or add his additional new hire year (if the TA passes) to his 1 year MD88 freeze. Total time from hired to released-from second aircraft freeze is identical.

This is clearly a concession for some. It makes the company more efficient at the expense of pilot flexibility. Whether the concession was/will be worthwhile is in the eye of the beholder. Everyone hired before 1 December benefits immediately, and after two years, new hires will also benefit some from (some) subsequent training freezes.