Infamous 2 cannot be the new uncharted 2 because if it did, it wouldn't be infamous, it would be the new uncharted 2 :p
The 2 games have nothing in-common other than being ps3 exclusives.
1) one is sandbox the other is linear
2) one is the 3rd person over the shoulder shooter the other is platformer
3) one is more action/ adventure and puzzle orientated the other is more platform and adventure
4) one can achieve high end visuals since it is linear whilst the other has set backs for having to stream a large open map
It is safe to assume that Infamous2 will be the new Infamous. This is why we should look forward to it. Be more of the same with improvements wherever possible.