I could see Universal "hanging on" to this area until the next three HP-world movies come out (sometime in '17-'18, I think?), the Fantastic Beasts & Where To Find Them movies, then retheming it to the movies and connecting it to Hogsmeade. Diagon Alley's expansion (whenever that happens) will be the Ministry, which obviously fits best there, while the Beasts world (which takes place some decades before the HP books) would fit best around Hogwarts/Hogsmeade. Wasn't The Lost Continent originally meant to be based around legendary mythical beasts in the beginning? I know many wouldn't be happy with HP taking over the whole island, but financially, this seems the most logical way to utilize this really great, overlooked area of IOA without completely ripping it apart, and the Fantastic Beasts might be less in-your-face-hp-themed enough to draw non-HP folks into the land.
From what I remember when I was working at the bookstore, the little book the movies are to be based on was full of commonly known mythological beasts and HP-related fantasy creatures and stories, which would translate well to the area even without the Wizarding World tie-in.