I was wondering if anyone has been to the mermaid show at Weeki Wachee? We are thinking of going during our daughter's wish trip, and I was just wondering what other people who have been during a Disney trip or otherwise have thought of it?
We drive to Disney, so Weeki Wachee was not far out of the way for us. It was worth the side trip to see it at least once. My kids thought it was pretty neat. There is not a lot to do there, except for watching the mermaid show, and there is a small animal show, and a boat ride on the river (we didn't get to do this though, because the wait was so long when we were there.) Like I said though, it wasn't very far out of our way, I really don't think I could justify a 4 hour trip for it though (It's about 2 hours north of Disney). However if it is something your daughter REALLY wants to do, I say go for it.
Also, just FYI, while Weekie Wachee is 2 hrs north of Disney, Clearwater is about 1 1/2 hrs south-west of Disney. I would not try to do them in the same day.
If you plan on being in Clearwater, I have another suggestion that may be even better than Weeki Wachee. How does your daughter feel about dolphins? Clearwater Marine Aquarium is just a few miles from the beach and is home to Winter the dolphin from the movie "A Dolphin's Tale". I noticed you said this is a "wish" trip for your daughter. Winter is a great little swimming role model for those with disabilities or illnesses to show them that no matter what happens, you just have to keep fighting. If you are not familiar with Winter's story, she was trapped in a crab trap and ended up losing her tail, she was rescued and has since re-learned how to swim, she even has a prosthetic tail she wears sometimes. It's very touching and amazing.
It's not a big place like Sea World, and if you go into it thinking that you may be disappointed. It's a small (rescue center/aquarium), they have about 7-8 dolphins, and many other rescue animals as well, like turtles and otters. Some of the dolphins put on a little show a few times a day, but the star of the place is Winter!! The people that work there are super nice and took the time to really talk to my kids about the animals stories. There is also the option to take a boat ride to their museum across the bay where they have movie memorabilia, a meet and greet with a character version of Winter, and a gift shop. My kids LOVED it!
Again, I don't know if this would be a fit with your family, but I just wanted to throw that option out there, in case you didn't know about this. One other thing if you decide this as an option, it's much better to watch the movie before you go, if you haven't already done so. It makes it more exciting for the kids to see things in person, that they seen in a MOVIE. Or at least it did for my kids.

No matter what you decide though, I hope you all have a great trip,

to your daughter and the rest of your family.