Can't find any info on the matter, but is the 4.0 expertise cap actually a bug or is ~172 the new cap? If it is reported as being bugged, has it been fixed in the latest hot fix or continue to be messed up? Thanks for any input.

Due to recalibrating expertise for Cataclysm, level 80-83 creatures (which includes bosses) dodge and parry less, so you need less expertise, 23, to be exact. Sorry we didn't announce this. I would classify it as an unintended consequence (though not unknown) and not a desired change on our part.

At level 85, you will need 26 again.