Why can't we change Runes in champ select? (Riot Response? :D)

This is probably my biggest inconvenience with LoL right now, and has been for a while. It just doesn't make sense to me.

I can change my Masteries in Champ Select, but if I happen to have the wrong runes for whatever reason, I can't change them?

If I want to play Talon, I should be able to put armor/MR runes depending on my match up.

I would think this wouldn't be too hard to change, so no point in ignoring it until the runes get rewrorked.

Just a slight problem of mine, i'm probably the only one...