PS4s are still sold out everywhere, and by sold out I mean you can't order them or anything. I know quite a few people who are interested in playing CoD on the PS4 but can't because they can't find one. If this trend continues, which it very well could, and these people don't get a PS4 until after the deadline to upgrade they'll be forced to pay $60 for a game the already own and play often.
So I think extending the deadline or at the very least pay ahead of time for the upgrade should be at least considered.
this would be a very smart move on their part especially for the xbox one platform as methinks a lot more will be sold in the coming weeks