I take this back - I've reviewed multiple logs from various classes/specs and I haven't found a single one that conclusively indicates a lowered proc rate. On the contrary, most of them line up very well with the theory that the nerf ended up lowering the chance by a third.
It definitely looks like it's back down to half its original proc chance rather than two thirds. I'd like to see a few more tests, particularly tests involving other classes, before I change it in the sim though.
If you can show me more logs with significantly lower proc rates, please post them here or in a PM to me - unless I see more I'll assume the logs/tests referenced above are simply "bad luck" outliers.