(In reply to comment #4)
> [...] since valgrinding 32 bit WoW on a 64 bit box is currently beyond me,

As suggested in your WoW bug report, please try valgrind on replaying an
apitrace instead.

> I am hunting for memory errors in other workloads instead, in the hope that
> they might provide some insight.)

valgrind finds one 352 byte leak with celestia. That can't possibly explain the
issues you're having with WoW.