Disney does realize that. Occasionally, in response to threads like this AND when time is available, one or another DISer will go through all the menus and post the "unique" items.
Yes, many restaurants have the same, boring kid fare - but as RustyScupper implies, that's at least partly in response to those being items kids will eat.
All items taken from the DIS's own
http://www.wdwinfo.com/wdwinfo/dining/diningmain.cfm, using its search tool feature. I did not look at the individual menus so cannot tell when each was posted. Remember, ALL menus online are subject to change - given that they're unofficial and generally provided NOT directly by Disney, but by site staff or users or both
ABC Commissary: chicken nuggets, fried fish
Artist's Palette: pb&j, chicken nuggets, macaroni & cheese
Yak & Yeti counter service: cheeseburger, chicken bites, pork eggroll
Backlot Express: chicken nuggets, chilled chicken & vegetables
Cantina de San Angel: grilled chicken & cheese quesadilla
Captain Cook's: chicken Strips, grilled cheese, turkey & cheese sandwich
Chakrandi: chicken soup
Cheesecake Factory: hamburger, hot dog, pasta
Columbia Harbor House: garden salad, macaroni & cheese
Cooke's of Dublin: fish & chips, batter-fried skewered chicken & chips, baby sausage & chips
Cosmic Ray's: mixed green salad w/chicken, chicken nuggets, pb&j
Disney Quest: pasta w/alfredo, pasta w/marinara, pasta w/meat sauce
Earl of Sandwich: turkey/swiss, pizza sandwich, grilled cheese, pb&j
El Pirata Y el Perico: taco
Electric Umbrella: macaroni & cheese, chicken nuggets, turkey pinwheels
All Star food courts: chicken nuggets, grilled cheese, pasta w/meatball
Everything Pop: chicken nuggets, grilled cheese, penne w/meatball, vegetable lo mein
Flame Tree: baked chicken wings, hot dog
Gasparilla Grill: hot dog, chicken strips
Goods to Go: hot dog, hamburger (meal in a bucket)
Hurricane Hannah's: chicken strips, cheeseburger
Leaning Palms: grilled cheese pretzel, hot dog, pb&j
Lotus Blossom: Beijing bbq drumstick
Liberty Inn: chilled chicken, chicken nuggets, pb&j
Lottawatta Lodge: hot dog, macaroni & cheese, turkey sandwich
The Mara: rotisserie chicken, macaroni & cheese, chicken strips, hot dog
McDonald's (DtD): hamburger Happy Meal, nugget Happy Meal, Mighty Kids Happy Meal
Old Port Royale: chicken nugget bucket, chicken drumstick, macaroni & cheese
Pecos Bill's: hamburger, garden salad w/chicken
Pepper Market: hot dog, pizza, pasta, chicken strips
Pinocchio's: pb&j, turkey roll-up, macaroni & cheese
Pizzafari: pb&j, cheese quesadilla
Rainforest Cafe: pizza, macaroni & cheese, pasta, hot dog, hamburger, chicken tidbits, grilled cheese, shrimpkens, shrimp
Riverside Mill: macaroni & cheese, turkey pinwheel, hamburger, chicken nuggets, fish basket, pasta
Rix: grilled ham & cheese
Roaring Forks: pb&j, chicken nuggets
Rosie's: macaroni & cheese, chicken nuggets
Sassagoula: chicken nuggets, pasta w/marinara, grilled cheese, pb&j
Studio Catering: grilled chicken wrap, pb&j
Sunshine Seasons: chicken leg, macaroni & cheese, sweet & sour chicken, make-your-own mini sub
Tangierine Cafe: hamburger, pizza, chicken tenders
Tempura Kiko: chicken w/vegetables, shrimp w/vegetables
Typhoon Tillie's: Grilled cheese pretzel, pb&j, macaroni & cheese
Food & Fun Center: hot dog, chicken strips, macaroni & cheese, grilled cheese
Warming Hut: pb&j, hot dog
Wolfgang Puck Express: pizza, chicken tenders, macaroni & cheese, grilled cheese
Yakitori House: Teriyaki chicken
Counter service with apparently no children's menu:
Asia Food Stand
Avalunch
Boardwalk Bakery
Boardwalk Pizza Window
Boardwalk to Go
Bongo's Express Window
Casey's Corner
Catalina Eddie's
Courtyard Pool Bar
Dip Site
Lowtide Lou's
Main Street Bakery
Marketplace Snacks
Safari BBQ
Safari Turkey Leg
Sand Bar
Siesta's Pool Bar
Sommerfest
Space Dog Hot Dog
Spoodle's Pizza Window
Surf Doggies
Grab & Go/Contemporary
Village Fry Shop
Pizza Planet
Wetzel's Pretzels
Yorkshire Fish & Chips
So, while yes, there are a lot of repeated items, there appear to be enough different choices so as not to have to feed a child a week's worth of macaroni & cheese (for example), even for Guests who dine SOLELY at counter service locations.