The good news is that the Iris Pro in the 15" can handle photoshop with ease. No problem at all, it's fantastic. Regarding games, you can expect to play them at 30-40fps with medium-high'ish settings at resolutions below 1080p.
We don't know anything about the future, so don't know about that. I'm thinking of buying now at a good price, enjoying till either Broadwell or Skywell, then selling and upgrade again.