All tires are build for traction, control and road holding - does different tire at front and back influence the function that is build for?? Unlikely - it is not ideal but don't see major issue at all - usually the front tyre worn out at least 70% faster ahead of the rear if its not rotated, unless you are really diligent going to shop to do that on quarterly basis, most will end up with uneven tyre wear - changing all 4 tyres are usually recommended by the shop - as it means customer spending more, shop will exaggerate the impact, otherwise its a non-issue..