Why arent armor penetration and lifesteal listed in stats?

What do you mean? If you hold C it will bring up more stats for you. If you mean being able to see the stats of your opponent, I agree that we need to be able to check it.

hold c, it makes an additional little tab pop up with those stats and more

IF you are talking about your own champion press C If you are talking about enemy champions i don't know whyt.

hold C dummy