Disneyland’s “Small World” will soon be getting a little more crowded.

The Anaheim amusement park is planning to add iconic Disney characters to the anonymous international cast of the beloved ‘round-the-globe boat ride. The idea has sparked outrage among the family of the attraction’s original designer and prompted a preservation campaign for the ride, which opened in 1966 and closed for renovations in January.

Walt Disney Co. isn’t saying how many familiar characters will appear in the revamped ride or how prominent they will be. But relatives of artist and ride designer Mary Blair sent a blistering letter to Disney executives last week, berating what they called an “idiotic plan” that “represents a gross desecration of the ride’s original theme.”

“The ride itself is a classic ride,” said Kevin Blair, the designer’s son. “They should leave the ride the way it was with the children of the world and leave all the Disney characters out. It just bastardizes the whole ride.”

Walt Disney Imagineering spokeswoman Marilyn Waters said a number of familiar characters would appear in “stylized” form in the overhauled ride and placed into appropriate countries. Mickey and Minnie Mouse are not part of the plan, she said.

The changes carry on Disney’s tradition of “plussing” attractions, Waters said, and help enrich the storytelling and keep the experience relevant for future generations.

“No one approaches our classic attractions with more reverence than Disney Imagineers, who take great care when refreshing beloved attractions,” Waters said, adding that the original intent and celebration of children will be “retained and strengthened.”

Some fans of the original ride, however, fear the changes are a crass attempt by Disney to make the attraction more commercial and sell more plush toys, dolls and other products. Many are posting plots and pleas on savethe smallworld.com and other Disney-related sites.

“I’ll sign any petition, wear any T-shirt or handcuff myself in a human chain to ‘It’s a Small World’ in protest,” wrote one fan. Another penned new lyrics to the ride’s iconic song:

It’s a world of franchise,

it’s a world of fun

Piles of plush mean profit

for everyone

Wonder, Magic of Dream,

in our marketing scheme,

it’s a mall world after all.

The criticism comes as Disney prepares to open its newest version of “It’s a Small World” at Hong Kong Disneyland. Thirty-eight recognizable characters, old and new, will appear in the attraction: Aladdin and Jasmine, from the movie “Aladdin,” will be in the Middle East; Woody and Jessie from “Toy Story” can be spotted in an expanded America section with the Golden Gate Bridge and Empire State Building. The song has also been modified, adding “familiar Disney melodies,” Waters said.

The changes that will be made to the Anaheim ride won’t mirror those in the one in Hong Kong, Waters said.

Ken Bruce, a former employee of Pixar Animation Studios, which Disney now owns, maintains a blog “for Imagineering and animation professionals to critique the current state of Disney theme parks.”

He said the “It’s a Small World” overhaul has sparked fierce debate about change and creativity. Most of the people contributing to his site want “Small World” kept in its original form.

“It’s job No.1 right now as far as we’re concerned,” Bruce said.

“It’s a Small World” is a “very cogent, carefully thought-out piece of thematic storytelling,” Bruce added. “To think that Disney characters are going to invade the place and take away from the rightful stars -- the children of the world -- is really scary for us. It’s Disney turning their backs on one of the classics and turning it into another marketing scheme.”

Still, for all the outcry, Disney has successfully refurbished other attractions, including “Pirates of the Caribbean.” Last summer, the Anaheim park added several lifelike animatronic Capt. Jack Sparrows -- played by Johnny Depp in the movies -- prompting complaints from purists.

But after the updated attraction opened, many fans grudgingly acknowledged that the lovable troublemaker had been seamlessly introduced and that the additions may make the ride more appealing to young park-goers who had seen the movies.

Of course, some park-goers who find “It’s a Small World” dull and its song saccharinely repetitive and cloying say Disney can’t do enough to change the attraction, which will reopen in November.

“What is the big deal?” one Disneyland fan wrote on Bruce’s website. “The ride is old, sad and boring. “Disney: Tear the thing down and put in something more interesting please!”

kimi.yoshino@latimes.com

Times staff writer Brady MacDonald contributed to this report.