Those 3 b-sides you mentioned, yes are quite good, but are not some the best songs the band have ever written. OK, they're probably better than the ones you say should have been replaced.

To be honest I don't think any sort of song rearranging or replacing on Crush would make any real difference to how good the record would have been. I don't dislike it, and never have, but I just have always found it a bit too bland. I always preferred Bounce over Crush.