The i5-4690 should last longer than 2-3 years. If it doesn't then everyone is in trouble, since there's nothing significantly stronger scheduled to release for the next 2 years at least. :3
Broadwell will be a bit of an upgrade, but nothing groundbreaking enough to cause developers to stress any current i5s, probably just a modest 5-10% improvement focused on low-power use, since it's an efficiency improving "tock" for Intel, and not a performance increasing "tick".
But yeah, the i5-4690 is a great CPU and won't bottleneck any two cards.