We should be able to see all the Runes in-game.

Seriously. I love the new rune system; I just think that, part of the strength of the rune system is there isn't as much subtle math to worry about. What each rune does and how much it does is easily understood after several games.

However, just knowing the Opponents Primary, Secondary, and Keystone isn't a complete picture. Do they have second wind? Are they running magical footware? Do they or don't they have manaflow band? Knowing stuff like this can have profound effects on matchups. This is valuable information that is gated to using 3rd party apps.

There's no reason the new runes should be something secretive, again the very strength of the system is it does away with much of the subtlety that was present in the old.