I don't expect entirely new gameplay, but I didn't expect a COD style rehash either. They could have done things like a new setting, new modes, changing the gameplay to differentiate from its predecessor etc. There's quite a lot of variance in military shooters too. Compare BF1942/BC2/BC2:V/2142/3 etc. they don't feature entirely new gameplay but they don't feel like rehashes either. BF4 on the other hand looks like a COD style rehash of BF3 so far.