The answer is simple: They only had ONE tester testing the MP mode
I recently took a look at the credits - please don't ask why. You can find them under Extras - Credits or here: http://www.allgame.com/game.php?id=53097&tab=credits. There is a category "Multiplayer Testing" and it shows only one name Whereas the regular testing team consists of 8 guys
The question is how did he test it all by himself? Only playing the computer using the "Player Match" mode without inviting anybody else? Switching between 2-4 XBoxes all by himself? Octopus-like number of arms? Schizophrenia?!
That would at least explain why they did not catch any of the button race and upgrade glitches (barb reward stealing, losing movement, rushing defenders during upgrade, avoiding diplo and all the other odd stuff that is so f*** up in MP but would never occur in SP).
Well, thought I would share that observation with you guys. I am not sure if it is supposed to make me laugh or cry