Wizards of the Coast, like many companies, is not led by the same people over the years. Leadership changes, Brand and Design teams change, restrictive partnership licenses expire, and as time progresses, opportunities occur to introduce new generations to older IP content are increased. And if they do it right, they hit the nostalgia button for older fans, and can create something memorable that can become the future nostalgia for a new generation of fans.
Some companies get it pretty right, and some miss the mark, but for the most part it is subjective. For instance there are different people from different generations who each think each one of the three Star Wars trilogies is better than the others.
Some people loved the easter eggs of the cartoon heroes showing up in DnDHAT, and even a car commercial!
Will Wizards do a good job with an adventure featuring the cartoon characters as pre-gens? Who knows? For one thing, it's going to have the unaliving of enemies, so it won't be the same energy as the cartoon.