I will see what I can find out. Usually if you refresh you can get it to come up (sometimes more than one refresh). The main reason this is happening is because people's wl are too big. But there is more going on now because the shorter wishlists are just as bad at this moment D:

This typically happens when the wishlist (not just the one page, but as a whole) has too many items to load in 30 seconds, so it times out.

There actually is an older report for this on the 🌟 Known Errors List - 11/9/14. If you don't mind, can you repost your report here: ☆ * Cannot Load Wishlists

It looks like Destiny has already made a note to the programmers, so we'll keep you updated if we hear anything. :)