Edit everything during loading screen? and what if Item sets are an tied in to masteries?

what if we could edit masteries and runes during loading? now it does not happen often but the one time you are stuck with the wrong masteries/runes is detrimental to our psychology as a player. nothing sucks more then losing a game because you lagged out during champ select and know that the result of the game might have been different.

and my second point. Many times i want a similar item build path for anyone that uses the same masteries but now that item sets are gone (although i only used it for my mains) many times if i have an off pick i spent a lot of time looking through items and usually end up deciding that i wana build the same as my main champ just because im used to specific items and their synergy with my playstyle