It's not so long, and I think that there are earning much more money from fees, then from interest rates from delaying users money. Dealing payments is not in their best interest, it would be better for them to raise fees - their will earn more and lose less customers. Bitcoin economy raised a lot last days, and there may not have enough people to process everything like usually.
That being said it is always good to force companies to offer us better service and exchange information about problems and deals can be a big problem for someone not expecting them. I am just not expecting mtgox to make delays intentinaly.
Use different ways to exchange your Bitcoins if you really want to harm mtgox.