Team Builder Possibility

I'm curious as to why Team Builder doesn't show the enemy team you'll be facing and thus give you the opportunity to change you masteries or switch rune pages like draft does. As it stands, Team builder can be a little punishing for those that want to be a champion that relies on certain rune pages for their matchups, and can be effectively negated due to mere chances. Some might argue that Blind deserves it, too. But I feel like the purpose of blind is to not know what you're up against, whereas the purpose of team builder is to build a team for that fight -- no reason to not know what you're up against.

Tl;dr I think Team Builder should show you your enemies and allow you to switch between rune pages, change masteries, and alter summaries like in draft.

Thoughts?