I wouldn't worry about the year 12 Geoff... There have been guarantees that the pass rate at each grade will be the same as the old system, so I suspect it will all work out ok..
The whole system is under tremendous strain though, the change to KS3/4/5 came in three years and with no additional funding (quite the opposite in my school's case).
This is further undermined by NiMo's competence. Academies? It only came about because she couldn't think what to do next. She's a very very poor education secretary. People may have hated Gove (for some good reasons), but he had a clear strategy, and a clear direction. If you could provide clear evidence why something was wrong, he would often change it...
Gibb is driving much of the reform, but sadly he's about as reliable as a 9 pound note. A few years ago (before they were in government), I caught him out telling lies in public. We had a heated email exchange in which he repeated the lie, I eventually showed him evidence which he could not refute.... So he blamed it on labour.... Not a terribly nice chap, or a terribly good politician.