First off, I call BS on the $17K discount on a 2014 Platinum, unless it had a lot of dealer installed accessories or services (lift kit, wheels, nitrogen, "lifetime engine warranty", clear coat protection, undercoating, etc.).
Farnsie, don't expect that kind of a discount on a "stock" truck.
The styling may not have changed, but there are significant improvements in the drivetrain. Check out this article:
http://www.internationalpowerstroke.com/2015-powerstroke.html
Every know issue with the 2011-2014 Powerstroke has been addressed in the 2015 changes. The turbo has been a weak point since 2011. This is easily remedied by purchasing an aftermarket kit that utilizes the same turbo as the 2015. The kit and installation will run you $4,500.00 or more.
I bought a 2015 King Ranch last week (2014 never came into play on my deal). Yesterday, I helped my brother-in-law purchase one as well. After working-over a 1/2 dozen different dealers, he bought a 2015
for $3,800.00 more that a comparably equipped 2014. Both of our trucks have the new and vastly improved King Ranch leather interior. Yea, That's a Styling Change!
So let's recap:
The cost difference between a 2014 and 2015 is about the same as a turbo upgrade, if you shop HARD.
The 2015 has many more engine improvements than just the turbo, not to mention 40 more HP and 60 more TQ.
The 2014 will take a more sizable depreciation "hit" once you drive it off the lot.
If you go with a King Ranch, you get much nicer leather.