You must see here that India are playing in highly familiar conditions. The last time we played a World Cup in the subcontinent, we won it. In subcontinental conditions, guys like Sehwag, Raina, Dhoni, etc bring out their best attacking game. The major problem we have is the absence of that one figure who lends balance to both batting and bowling and is highly influential with his exploits in T20. Yuvraj fits that bill.
I still maintain that without Yuvraj, we have a 50% chance and with him we have a 80% chance (atleast!).