Knee-jerk reaction is to flame Jagex for even more unpolled changes. Having said that, the gmaul needed a nerf. Bulwark too, but going from 18 to 0 is a little overkill. +6 or +8 would have been more appropriate, imo.
I'd be interested to know why you think +6 or +8 would be more appropriate. Why have you picked those numbers?
Unsurprisingly, PvPers are saying the change was too small rather than too large. We went with the smallest change that would still have a significant effect so we could monitor it and adjust further if needed. I think reducing it to +6 or +8 wouldn't make much of an actual difference in terms of how often a freeze catches.