Gaf is annoying me quite a bit right now by having so many people put God of War, Spiderman and Days Gone as 2018 and 2019 releases. No way in hell isn't at least one of these looking at a 2017 date, I wouldn't be surprised if all 3 were currently aiming at that window.
Bend has gone too long without a release for Days Gone to not be a late 2017 title. Plus, we saw substantial gameplay already and enough details were revealed half a year ago to suggest that development had reached a point of bringing it all together instead of still figuring out what stays and what goes.
For God of War, I'm actually banking on that being an early 2018 title. For one, that's usually when the franchise has a release. In fact, with the exception of Ghost of Sparta, every single God of War title has released in March. When Barlog rejoined Santa Monica, both Todd Papy and Stig Asmussen were still with the studio. Meaning they had three directors but not enough people for three separate teams. Barlog had mentioned recruiting people for a big project. So it seems they had every intention of expanding even more. Later that year, Todd Papy left which likely meant whatever his team was up to was either scrapped, it was another God of War but Barlog had his own vision for the game and changed it substantially, or a majority of them were shifted to Stig's failing project in an effort to save it before the plug was pulled and many of them lost their jobs. Which ever was true, after the disaster of Asmussen's project, it's pretty clear Santa Monica was in a bind and I'm willing to bet everything ground to a halt while they reorganized themselves. This new God of War COULD have been in development for over three years now but everything I've seen and heard suggests to me that it hasn't actually been that long. Almost as if another God of War wasn't originally in the cards and after shame hit the fan Santa Monica ran back to the one thing they know for sure.
As for Spiderman, that just depends on how much Insomniac shows between now and next E3. They did say they're working on stuff to show us next year and it really wouldn't surprise me if Sony tries to line it up with Days Gone as their second half showing for 2017. Detroit possibly being part of that group.