Hollywood Studios is my favorite park, so take that for what you will.
People really need to learn the difference between an opinion and a value judgement. Both are subjective, but for some reason, while we all understand that opinions are personal, so are value judgments. Liking or not liking something is easily as subjective as worth it or not worth it, but people seem to think that everyone's value systems are the same.
I really enjoy the classes of rides at Hollywood Studios. I like that two of my favorites are right next to each other (Rock 'n' Rollercoaster and Tower of Terror) so I can run between them repeatedly. I really love Star Tours. I'm a movie fan, so I love older attractions like The Great Movie Ride. And I love that they're all in the same park.
I like the atmosphere most of all, and I could spend hours just taking it all in. That right there seems to be the biggest differentiator. You either enjoy spending time at a park or you don't. Really, riding the rides is the least amount of time you will spend doing anything. Experiencing the atmosphere of the space is more important in that regard, and some people just don't care for it, going only for the ride experiences. Of course you'd consider it a "half-day" park in that case, because there just aren't that many rides.
For someone for whom the rides are not the end-all, be-all of a Disney experience, or someone who loves the subject matter, it could be a full-day park or more. I tend to take two days there because I enjoy it so much.
Anyway, the point is, you can't expect anyone else's value systems to match yours. Go see everything and decide for yourself, and try not to let your opinions color other people. I made the mistake of deciding Animal Kingdom wasn't worth going to on my very first trip because "I don't like zoos." Turns out not only do I like zoos when Disney does them, but I enjoyed everything else, too.