The base crit ratio for a wizard was 100% even without AAs. I played one on the Combine progression server and specifically remember critting
Icestrike while I was still a lowbie. It would always be for twice the normal damage. (So 32 damage instead of 16.) I used the spell even into the 30s and 40s just because it was so ridiculously mana efficient, even more so when it would crit.
Sad that it took AndMetal's suggestion there to remind me of it, but that's absolutely correct. And I remember critting
Conflagration for 1800.
If anything, I would be that what KLS has posted from the changelog was to fix a bug. Someone with only one or two ranks trained in SCF might've actually seen their damage drop, and then seen their criticals back to +100% damage at rank 3. That would be my best guess.