A lot of people agree. But there are some who use team chat to make fun of the other teams, and they don't want that revealed, so the idea never gets far. Cowards put a damper on education.
This idea has been suggested and rejected multiple times for the reasons that BaldAdonis mentioned. Please use The form for future suggestions.
Thanks, and have a wonderful day!
jm
also, if your well-thought-out strategy is put out in the open at the end of your team game, that would probably really discourage the strong teams from using the in-game chat...