Young Link is pretty much one of the few Nintendo characters that I would, without any hesitation say that he has absolutely no chance at all. Never mind the fact that he already has been replaced by a character who not only fills his role very well, but might as well be the same character as Young Link. He has little marketing potential precisely because he is the exact kind of character who has no real appeal due to Toon Link making him redundant. How many people are honestly going to be interested in Majora's Mask due to the inclusion of a redundant (and yes, considering Sakurai's philosophy on the Links and the fact that Young Link already had an established moveset with Sakurai showing reluctance to completely chance clone characters as shown by Ganondorf still having many moves in common with Captain Falcon, he is going to be an absolute clone) second child Link? Young Link isn't even a popularly requested character
More importantly he doesn't fit into
any of Sakurai's criteria except fitting into the style of Smash Bros, which means nothing. He neither has appeal nor the Smash demand to make people want to play the game. He is not unique at all and he has no chance of becoming unique considering the history of veteran clones and the fact that Toon Link, a character that could have been unique, was turned into a clone because of Sakurai's philosophy regarding Links. Another Child Link that is a clone is redundant and thus he would absolutely do the opposite of contributing to game balance.
Young Link sticks out as a sore thumb and a nonsensical veteran inclusion for all the reasons that I have explained. Sorry, but there is no way, even as a easy clone addition, that Young Link will ever be DLC especially as the one supposedly "advantage" that he has is made moot by just how little appeal he has. If you ask me, Toon Zelda trumps Young Link in mere chance and she has over 20 times the chance he has (and that's not saying much, considering even 0.01%> 20 X 0!
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). Neither are popular, but at least she was planned for Brawl (as opposed to, you know, getting replaced by a character that is essentially the same thing as you and who takes your value and role away as the definitive Child Link). She also has had prominent post-Brawl appearances such as Spirit Tracks and WindWaker HD. More importantly, at least she wouldn't be redundant even as a clone, considering there isn't even a Zelda clone let alone a Child Zelda who is a clone.
In conclusion, can this ridiculous notion that Young Link remotely has a chance end? He is a terrible choice for an advertisement character, any importance he has as a child Link is moot due to Toon Link, he has no real appeal due to being yet another Link and a second, redundant Child Link, he has not only been a character that never was planned to be in Brawl but outright replaced and he doesn't have much Smash popularity.