Why are they still talking about old Arisa vs new? She got her memories back at the wedding.
Not all of them
Its not just that- when you get your old memories back in cases like this, you don just go back to who you were- you just got some memories back- but the you who has existed until then - the 'new' you doesn't go anywhere- its not like the old memories overwrite your new personality. I mean you will change some as you get more of your old memories back, and be closer to how you were, but you cant undo all the changes that have happened.