Originally Posted by Ryllau Ellemayne
I know in Kayle's (or Morgana's) It said Morgana made a pact with the Summoners and Returned with NEW powers so.
It could just be referring to a change in the power she possesed when she lived in her home world and not necessarily an augmentation of exeisting powers.
As for 'nerfing', it is quite possible that magical limiters are placed on a champion's powers. I mean, if the summoners can prevent Demacians and Noxians on the same team from destroying each other, then perhaps they can create magically imposed limitations on a champion's power.
I, personally, don't think that summoners would normally augment champions' powers as they do
wish to try to maintain the objectivity of League battles.