This I believe is a very good idea. I have an iPhone 5s now and while I plan to upgrade to the 6 I will say this... The iPhone 5s hasn't even reached it's complete ceiling yet. Apps are still optimized for the iPhone 5 and not the 5s which means no many is 64-bit...
The one thing that could hurt it is the amount of RAM it has, but rumors say the 6 will have the same...