Some pics to show the difference:

Redshirt Pre-S5 Patch - 29.3
http://img836.imageshack.us/img836/4...0111202145.png

Now - 27.4
http://img16.imageshack.us/img16/244...0120114123.png

Well there's 1 less engine power point in the current game due to efficient trait nerf but if I set engine power to 59, the turn rate still only goes up by .5 to 27.9. So lmost 2 degree loss! Aegis engine is even lower at 26.8 degrees, so its not just a borg engine nerf, unless every engine was nerfed.