Quote Originally Posted by Anza View Post
Increasing stack size should not affect game balance.
The standard reply to this is something about it affecting crafting and prices on the AH.

Given that, if the stack size is to remain the same, perhaps oil could be put into bags, that themselves stack to 99, but dispense a stack at a time? You'd be able to carry them like any other toolbag, and they'd hold as much, but the stack size wouldn't have to be changed.