think of agent smith in the first movie as a base model. when neo entered his shell and made smith explode, he got an upgrade. and like fingerprints, every other human he copied provided a different kind of upgrade, and downgrades in some cases maybe (like $2 hookers, crackheads, serial killers). when he copied the oracle, it was like a BM getting upgraded to a ferrari...
my theory...
the programs or RSIs that smith takes over doesn't have the copying ability. so let's say that the oracle smith decided to take over, lets say a $2 dollar hooker... smith is the only one doing the copying and the oracle part is left out because she doesn't have the ability to replicate. it's like the right hand has no idea what the left hand is doing basically...