Summoner spells and runes.

Today I was playing a match and I made a mistake choosing my summoner spell. I thought it would be nice if I had unsealed spellbook to change it but sadly I didn't. Then I got an idea, since forgetting a summoner or runes happens quite often, what if we could change it in game. Now I don't mean at any point in the game, but before you move out of the fountain for the first time, or maybe in the first 30 seconds. Now the problem would be that we would know from the loading screen what summoner and runes they have and we might be able to take that to our advantage. I guess an easy fix is to just remove seeing opponents summoners and runes until they appear for the first time on your screen (like levels and items work). Thoughts?