I don't think Fox is bad enough yet, but they're certainly getting there, especially with their unjustified double-dips (i.e. having a SE already finished but holding it back to release a standard edition first).
I'd say Sony and Universal are pretty much a tie, with Sony having the most pointless double dips (i.e. Stand by Me Deluxe, Big Fish Deluxe etc.)
Universal and Sony. The worst part is that a lot of times it was the same exact transfer, just repackaged. If you're going to reissue then at least improve it.
Sony's about to release the 4th version of The Mask of Zorro, so I think they win the title. Universal is one of the worst though since they often remove features from the newer version, such as the trailers on the Jaws 30th anniversary set or the commentary and DTS track on The Bourne Identity Not-So-Explosive Extended Edition.