A.I. in MUGEN IMHO is one of the hardest things to code. Providing different A.I. levels option is nice though!
In Thor case the normal A.I. has more Var(59)>=1 triggers than the easy A.I. does. You can compare both *.cmd files to find all the lines with "Var(59)>=1".
Thor easy A.I. focuses only on defense moves like guarding/blocking, guard pushes, air recovery,...etc.
Thor normal A.I., on the other hand, focuses mostly on attack moves and combos, in addition to defense parts
Oh I think it is not appropriate to use one MUGEN character's A.I. for another MUGEN character.
Thor's A.I. is not going to work for like Superman's. If you want to add/remove/strengthen/weaken a MUGEN character's A.I., then you have to study its MUGEN code very much in order to be able to change its A.I., provided that you have already understood most MUGEN coding features and limits..............this is from my MUGEN making experience..........anyone please feel free to correct my wrong and/or supplement anything missing.......