I think the XBO and PS4 are both 8 core so surely that's a good step in the right direction? I definitely think games will soon takes advantage of more threads, plenty of games out now can make use of more than 4 cores that's for sure!
Some game engines are already optimised for 8-cores and unless your gaming in 1080p most titles are GPU bound. Before Zen how many generations of Intel desktop CPUs were 4-core and 8-threads? Whatever your position on Intel vs AMD at least competition has driven off Intel’s complacency!
The long term concern for me is how Spectre and Meltdown et al will impact multi-threading on quad-core CPUs.