Enemy Armor pen, Magic pen, and Lifesteal should be easy to see.

With armor pen being so abundantly present in the game, I think it is time the enemy player's in game champion stats started to show this. Currently it is hidden and can only be found out by adding the items, and unless you use a third party program/website to see opponents masteries and runes, you have to guess the additional amounts they may have. We should see magic pen as well.

Also, with Warlords having inconsistent, to an extent, values of lifesteal, it would be nice to see just how much your enemies are healing for each auto. Also, same reason as with knowing just how much armor pen you enemy has with masteries and runes.

Most of this is QoL stuff, but it can be useful to know, especially at early levels.