My hopes are up for BF3. After the flop of Black Ops, I am in no rush to buy MW3. But I will check it out when it is launched and various reviews have been conducted. I have a feeling that BF3 is going to be huge and that Activision are trying to adapt MW3 to suit those who like BF3. For instance, the destructible environment and larger urban environment sounds very Battlefieldy.
They need to use the engine used in MW2, it worked well. Just give us dedicated servers, larger maps and something new... They shouldn't develop another engine just so that it can be over-glorified.