Chariots are not that bad at all. All you need is some experience (for you and the troops ).
In the beginning they die like flies. Try to train them. Attack weak rebel formations. They are also hard to control. But once they are experienced and you know how to use them they are some of the best shock troops I ever used.
First they are excellent against cavalry, regardless what kind of. They just eat the enemy!
Once the enemy cav is done you can flank the enemy and hit it in the side or back. Always keep your chars running, never stop them! Chariots do not kill as many inf. men as other heavy cav but it sure makes them route better than any other unit. Then you can use the (rather useless) rest of your army to chase them.
Playing Brits my chariots won every field battle.