New pads and cables are simple and easy to do but the question which comes to my mind is how do the brakes work, that is, how do they stop the bike? Having a rock-hard lever feel does not equate to having effective brakes. Certainly there should not be slack or friction in the system but keep in mind that you are using a rather powerful lever system to squeeze rubber brake pads so you will still be able to compress them long after the brakes are locked up.
I am not certain what your major tune-up addressed but it would certainly be worthwhile to go over your system and address any shortcomings such as excess housing length, housing ends not squared off, lubrication and the like, but if you can pick the rear wheel up with the front brake and lock it with the rear one you cannot make much meaningful improvement.