Rotating tyres every 10,000km will keep your tyres wearing properly. Front tyres always wear a little faster than rears because you are constantly turning them which causes more stress/wear. Rotating these tyres to the rear, and moving the rears to the front will keep all fours of your tyres wearing evenly.
Wheel balance can be thrown off by many variants including: Tyre Wear, Rust/Corrosion, Pot Holes, Weights Coming Off. Having a set of four tyres balanced while they are off the vehicle for a rotation is never a bad idea.