The fishing tournaments are the poster children for everything that is wrong with cross-realm zones, at least in the eyes of those that don't like the feature. Currently (or well, previously) if you attempted to win the fishing tournaments after patch 5.0 you had to compete against all the other players in the cross-realm zone group. That made winning the tournaments extremely difficult.
Blizzard has responded previously that this wasn't the intended behavior and that they were working on a fix. We now know that they've got such a fix, and it won't be able to be put in place until a patch is applied. As such, the fishing tournaments are being disabled for the time being.
Vaeflare also noted in the blue post that they're getting ready to address a number of concerns over the cross-realm zones, so stay tuned for more info on that. His full blue posts is as follows:
We've looked into this issue and have a fix in the works to make the fishing tournaments behave in a more predictable manner. Unfortunately, this will require a patch in order to take effect, so we are disabling the fishing tournaments until we can deliver the fix for them in a future patch.
As a side-note: we'll be posting about some larger CRZ concerns in the very near future, so hang in there. We're listening, and we're working to address those concerns just as quickly as we can.