If you need a computer now your decision is made. The 2015 MBP 15" is still one of the best laptops out there. For example:
http://www.laptopmag.com/articles/laptop-brand-ratings
If, on the other hand, you belong to a techno ApplePhile cargo cult then by all means keep facing west and pleading for their next offering.
And then be prepared to wade through ponderously long threads about how Apple has lost its way and become too iOSy and that it doesn't have ports every computer should have and a graphics card that is four months old and it won't run Leopard and how could Apple be so awful and, well you know.
Besides, you could always sell it. While I'd expect some drop in price I've seen used MBP's going used now for only about 20-25% under their list. So say in the US you'd lose $500 or so in value, depending on specs, which depending on the length of ownership (say 6 mos while everyone at Macrumors finds out what's wrong with the latestgreatest) might not be a bad deal.
I just bought one, and one factor was that I didn't know what the new one would bring. I wanna SD slot, for example. I don't need much smaller, which is why I'm going 15" anyway. I want something with a track record, although MBPs generally are exactly cube risky. I actually need to do stuff, so features I might not even need and incremental speed boosts are meh.
BTW Adorama and B&H seem to have the best deals right now, better than Apple refurb if you take tax into account, and maybe even with that depending on your location.