I live near NYC, and I think I judge the food pretty objectively. Some food opinions are probably inflated due to factors such as the
DDP and being in Disney, but you have to factor in that the judgements are relative.
The tuna sandwich at CHH is very good relative to other fast food locations. For example, I'd say it's better than Cosi, and far better than most of MK's other options.
Le Cellier's steak is a unique situation. I'd say the steak itself is on par with Outback's filet (which is fine), but the truffle butter is a really nice addition that you don't see even at higher end steakhouses. That said, Le Cellier stands out compared to most of the park restaurants (I'd say Epcot on the whole is full of overpriced, tame versions of what Americans expect to be ethnic food, while Coral Reef is worse than Applebee's and Garden Grill isn't even popular for its food). That said, I think the cheese soup is better than ABP's cheese soup, but not something that deserves the raves it gets.
I actually think Yachtsman is better than Ruth's Chris in every way aside from the entrees. So I think the steak at Yachtsman is hyped, but the rest of the menu is pretty consistent with Disney's other signatures. Most people say that Yachtsman is the best steak on the DDP, which shows awareness that steak off the DDP (such as at Shula's) is better.
Some snacks might receive a lot of hype, but that's more telling of their uniqueness. I can find frozen yogurt anywhere at home, but I've never seen pineapple soft serve anywhere besides WDW and
Disneyland. So that makes the dole whip a really enjoyable treat for me. Plus, the pineapple flavor doesn't taste artificial (can't say the same about the orange), which makes it better than most of the fro yo near my house.
In terms of the signatures, I think Citricos's food scores are rather inflated. I've had better, more creative Mediterranean fare near my home for much less money. However, there are very few restaurants near me that serve food like Jiko or Artist Point. Jiko is higher quality (but less authentic) than the one South African restaurant I've been to in NYC, while the salmon at Artist Point was better than the Alaskan king salmon I had at Morimoto. However, many people say California Grill has the best sushi they've ever had, but I don't think California Grill's sushi was better than Morimoto's (but it's far better than my local sushi place).
Then there's Ohana, one of the most popular Disney restaurants. I have to say, Ohana has far less meat variety than Fogo de Chao, but Ohana's meat quality was similar. In fact, I'd say Ohana's chicken was more moist than Fogo's, and I actually preferred the oak-grilled flavor of Ohana's steak. Ohana's sides aren't as good as Fogo's salad bar, but Ohana costs way less than Fogo anyway, so I think Ohana would fare quite well even in a non-Disney setting.
So I do think Disney dining has some establishments that aren't too inflated when compared to similar places outside of the world. It obviously depends on personal experience (there are quite a few restaurants that are too dumbed down and mediocre for us to ever return to again), but that's why it's good that Disney has variety. You don't have to eat at Disney's hibachi restaurant or diner-style restaurants or whatever if you don't want. Unless you eat at French Laundry or Per Se or Le Bernardin or Alinea or Manhattan's finest restaurants all the time, the odds are pretty high that WDW will have something that's unusual to you or at least comparable in quality to similar food at home. As for being overpriced, I think that's a separate issue, but that's something Disney does on purpose to make people more likely to purchase dining plans (because that $59 surf and turf at Narcoossee's was so much more enjoyable when you used credits on it instead of paying cash, even if it didn't taste any better than lobster that costs $20).