This seems more like an early tactic to squeeze extra cash out of the consumer before playing a marketing mind game. So when the price drops to around Sony's PS4, everyone will be like, "OMG what a deal, it used to be a lot more!!" I'd love to say that wouldn't work, but the majority of the US and gamers as a whole, are known for their ability to not see a scam coming from a mile away. >__>
TC, if Halo 5 is the only exclusive you are wanting I'd say wait. H5 is likely November 2015 and by then it's very likely the price will have dropped and there will almost certainly be a bigger HDD in it.
Until there are enough exclusives to justify the purchase in your mind stick with the PS4 for it's exclusives and better multiplats.