Watched the episde and my God, I loved how they made Lucario going completely berserk and fighting so brutally; I really liked the choice they made.
In any case I'm loving Korrina more and more, because she's adorable, funny and also determined to reach her goals.
You could say she's a female Ash.
As for her realtionship with Lucario, I think they're doing a great in work in portraying it and developing it.
I do hope that she will stay with Ash and the others for some more and also I wish that she could stay with them for the rest of the adventure, also because she deserves being so relevant in the plot, considering how much info she has given about megaevo; but that's just my opinion.
Looking forward to watching the next episode, in which, probably, Lucario will be able to control himself.