I do not know how the food is in the fancy schmancy restaurants of theirs, but according to many food reviews here, maybe a little bit better!
I don't know where you've been eating, but the "fancy schmancy" places are REALLY GOOD. There are even non-expensive fancy places that are DELISCIOUS!
Try Teppan Edo at Epcot. Teppan-Yaki style, descently priced, and SO GOOD!
Lunch at Liberty Tree Travern (Magic Kingdom) was pretty good when we had it, but I think they're changing the menu soon (if they haven't already)...so I don't know how that would be now.
Donald's safari breakfast at Animal Kingdom - SPECTACULAR! Their pizza place was good too.
In my opinion everything at Hollywood studios pretty much sucks, so I would recommend staying away from food there all together.
If you don't want to leave Disney and go "off property", then try a hotel. For instance, Boma (buffet at the Animal Kingdom loge) or Chef Mickey's (buffet at Disney's contemporary) are both really good. Chef Mickey's is character breakfast, so that's ALWAYS fun.
Unfortunately, the cheapest hamburger they sell might not be the way to go if you don't like it. Disney is expensive...but it's Disney. My husband and I have found that it's better to pay more money for a good meal and get full than pay a lot of money for cruddy meals where you never feel full. In the end, it saves us money because we're satisfied and not eating as much.
Sorry you had such a frustrating meal experience. I've had a few of those at Disney, so I know how you feel. You could also get a villa and have a full kitchen where you buy your own groceries, cook your dinners and take your own food to the parks. It's cheaper for the food if you want to do that on vacation - but the villas are expensive! BUT - if you want to go this route they actually have grocery places that deliver directly to your villa...and other than a small $5 fee, it's only the $5 plus the cost of groceries.