[BostonCard]

 However, today he would probably be called for targeting and have to sit out the rest of that game and the next.  Boy would that have been devastating!

Hmmm. Maybe. 
It looks pretty brutal, so he may have been called for targeting regardless of the details. 
Luck mostly hits Wright in the chest, which is fine, but may also clip Wright's face mask. 
Luck probably also hit Wright with the crown of the helmet by the most liberal definition.

However, on the same play earlier USC #23 hits Taylor with a helmet to helmet shot to cause the fumble that absolutely should have been targeting - though I suspect the ref didn't see it. On the replay below I didn't really see it until the different angle replay at about 1:18.

https://www.youtube.com/watch?v=RF9PFJI_t5I

I think if you look closely at the replay, Luck gets him more with the shoulder than with his head, Luck clearly wraps him up (rather than launching at him) and you can see Luck look up at the target, so it is not a true targetting call.  In fact, if you freeze frame at the 42 second mark, looking at the play from behind Luck, you can see that it is a picture perfect tackle, and Luck's shoulder is planted firmly in the defenders chest.  As you point out, it may have been called just because it "looked bad", but I think it was a textbook tackle.

BC

[BostonCard]

 However, today he would probably be called for targeting and have to sit out the rest of that game and the next.  Boy would that have been devastating!

Hmmm. Maybe. 
It looks pretty brutal, so he may have been called for targeting regardless of the details. 
Luck mostly hits Wright in the chest, which is fine, but may also clip Wright's face mask. 
Luck probably also hit Wright with the crown of the helmet by the most liberal definition.

However, on the same play earlier USC #23 hits Taylor with a helmet to helmet shot to cause the fumble that absolutely should have been targeting - though I suspect the ref didn't see it. On the replay below I didn't really see it until the different angle replay at about 1:18.

https://www.youtube.com/watch?v=RF9PFJI_t5I

I think if you look closely at the replay, Luck gets him more with the shoulder than with his head, Luck clearly wraps him up (rather than launching at him) and you can see Luck look up at the target, so it is not a true targetting call.  In fact, if you freeze frame at the 42 second mark, looking at the play from behind Luck, you can see that it is a picture perfect tackle, and Luck's shoulder is planted firmly in the defenders chest.  As you point out, it may have been called just because it "looked bad", but I think it was a textbook tackle.

BC