I totally agree. We live in Miami, so it's not such a bad drive for us (maybe 4 hours). My mom is a huge Harry Potter fan and when we took her to Universal last year we spent almost all our time in that land, but surrounding it is basically empty space; the area set up like a middle eastern market has almost nothing to do. I am looking forward to seeing Diagon Alley, but that's about it.
An even bigger problem for me is that there are two parks, and two admissions. We like the rides at studios, but Wizarding World at Islands of Adventure. As you said, nothing to do there in our opinion other than that. It's just a long walk through a bunch of boring lands. I believe Seuss, and "Lost Island" or something. Neither were all that impressive to us. When we got to WW, we were lucky enough to be able to eat at the Three Broomsticks, and we snuck in the exit of Olivanders by accident to get out of the rain, so we didn't have to wait in the 2 hour line. Then we went to get a closer look at the castle, decided it wasn't that worth it to wait in line for the ride, so we just walked through. My wife rode the Dueling Dragons, but I could not because my ACL injury was at serious risk because of legs being able to flail around so violently.
So after maybe 3 hours in the Wizarding World, we had done everything we cared to do, filled up on butter beers, and were ready to head back (after knowing how far the long walk is from the entrance). Universal doesn't have the "wheel and spokes" that MK has, nor the ferrys to get you across the giant lake like Epcot has. It's just an unavoidable walk. Which, for me, spells a shorter day, because of my knees.
I also didn't like their attempt at the fast pass. Pay more, shorter lines. I'm sure it makes sense for them, but it doesn't flow nearly as well as the fast pass system. I also just don't like the idea it. Never been the class warfare type, no matter how minor the situation is.
Combine all that, and you get a little bit of magic, and a Busch Gardens/Carowinds/Six Flags experience, where I have to spend TWO park admissions to get 3/4 of a day at the very most of stuff to do...whereas a few miles away, you get to go to another world and an experience like no other for almost the same price.
Some will say all this stuff doesn't matter to them or I'm dead wrong (or you might say I'm just finding a reason to hate Universal because I have some mysterious deep seeded hatred for them and a bias for WDW, in which, you'd probably be right). I respectfully disagree with those people and encourage them to go wherever they like most, I'll be in the World though.