I too dont aggree that Managers can change tactics when the Games go Live... its will be give stress to the server just because the Game Engine needs to simulate the full match 2 times first is for your half time... then after you seen the result at the 15 minute halftime break... all the tactics you want as a Manager/Team owner should have been prepared before the match... then let your Coach/ Game Engine dictates the game... just to be fair... imagine how much damage the above suggestion will do on International Games between the Teams that is half the world apart...
If there should be some Tactical changes as an option to be implemented... then that should be included at the current Setup page... and would not be accessible for anyone after 15 minutes before Game time... as ussual..