the thing is micro USB isn't designed to deliver much power, it's alright for a phone but not so much for a tablet (it'll charge but slower) so it makes more sense to go with a single proprietary connector for all their devices rather than fragmenting the connectors in their own product line.
A cable is a cable assuming they are the same AWG, which basically all phone cables are. The thing controlling how much power is delivered is the wall adapter, which will take any standard USB cable, whether it's an apple cable, micro or mini USB, etc...
