T-20 is really unpredictable as you said, people said before tournament that england and india are favorites. India was not even able to make it to the semi finals and england were beaten by newzealand in the semis. I dont think any one predicted these teams to play in the final and that is the beauti of t-20 cricket. Hoping for a really exciting final just the the semi finals.
Even if you see odds of Pakistan v India game, Pakistan was no way near to India. Infact India was hot favorite for the tournament but beaten easily by Pakistan( the underdog) in the first game. Side batting first will definitely have edge over side batting second.
Not only T20, cricket is old funny game and can't be predicted in advance.