I don't have a problem with it being there from the beginning, it was something I feel like JK conceded since she wanted to see it built.
However now it is unnecessary, not because it doesn't belong but because a superior version with better capacity will exist. Why keep the original that simply isn't properly built to handle the HP crowds? Anyone who cares enough to go to Ollivander's (and will fork out the cash for a wand) won't think twice about upgrading their ticket to a Park Hopper.
I'd say convert it to another unique themed retail space, or a quick serve (like a bakery?). There are plenty of really great things in the HP universe that would be unique and most importantly - sell more stuff!