Nope. The Core i5 isn't mid-range, it's actually high end for gaming, the Core i3 is midrange for gaming. Core i7 is just the champion for video editing. So, that Core i5 will handle the GPUs perfectly.
Hmmm.... the most powerful non Hyper Threaded CPU consumer CPU offered by Intel... bottlenecking XF 7870's... ABSOLUTELY!!!!
I say you should immediately stop playing games altogether and wait until 2016 when Intel releases Skymont. Maybe then Intel CPUs can manage to get more than 15 FPS in games. Lock away your Radeon HD 7870 'cause by then they will be worth their weight in gold.