I've never had anything at a Disney restaurant that was inedible, counter or signature. I've had bland, I've had cold when it should be hot and vice versa but it was still edible.
Places that are off the list pretty much for eternity and beyond: O'Hana's, tough cold meat, cold noodles, sweet salad dressing, I leave it to those who love it. ABC Commissary, edible but it doesn't stay in, not to be indelicate. Tony's, I'm a lover of red sauce, theirs nearly killed me with indigestion, not once but twice.
Usual faves that have disappointed of late, thus giving them a rest: Brown Derby (poor fish, lousy pork). California Grill (poor scallop, even poorer fish) and Jiko (sub the wild boar for pork, nah!)
New Surprises: Satuli's Canteen, QS Pandora, love those bowls.
Continual faves that never disappoint: Raglan, love, love love and there's Ger's bread pudding, Wolfgang Puck Express, Bacon wrapped meatloaf, Chinois chicken salad, Sci-Fi, the reuben (rest in peace) and fried pickles, Monsieur Paul's all of it, The Wave, great bar, wicked grits, Spice Road, yum, Marrakesh, love cous-cous, Wine Bar George, skirt steak platter, Frontera Cucina anything w/ salsa verde, Il Mulino, Blue Zoo, Citricos, Chef's, I love snails, Morrimoto's, Peking Duck, Mama Melrose, yes I too was surprised, pork saltimboca, Olivia's, conch fritters and fried chicken, Turf Club, lamb & beef any which way, Biergarten, love German food and BEER, which is only enhanced by the oom-pa-pa music. Rose & Crown, those damn Bangers and Mash, Boma, love the selections of soups, salads and bread pudding, and yes LTT, pot roast and that damn Ooey, gooey cake. I could go on and on.
If your best meal was at the Fish & Chips stand, it's all yours. But I will say, if my food was inedible, as you described or a steak which I enjoy med/rare came to the table as a burnt hockey puck, lol, I wouldn't "whine" about it but I would certainly bring it to the attention of my server and/or manager and I most certainly wouldn't pay for it. Thankfully I've never had to do so.