You know, since Sakurai already has so much time to do DLC, I could see Young Link getting changed with only his specials, his normal attacks and grabs will probably not change since they are pretty much fine on it's own. Toon Link and Link already take so much of what Young Link stand-out, so why not change his moves, it wouldn't really alienate the fans really.
The only special moves that I would personally like to see for Young Link is this:
Neutral-B: Fire Arrow: The same as in Melee, with the same hitstun and able to inflict damage even after rhe arrow is shot.
Side-B: Zora Boomerang: Link turns into Zora Link to throw two multi-hitting small fin boomerangs at the opponent, great for keeping out of range of the opponent, however he's unable to move and he has to wait for the boomerangs to come back in order to move again.
Down-B: Goron Roll: Similar to Sonic's Down-B, only much stronger and slower. It must be at full charge in order to Goron Link to damage opponents. If uncharged, Goron Link will just pass by the opponent where he's open to attack.
Up-B: Deku Flower Flight: Link turns into Deku Link to fly with his swirling flowers, has a glide effect and is able to shoot Deku Nuts straightforward in the air. The flowers also do multi-hitting damage too if an opponent tries to hit from above. If an opponent manages to hit him, he'll fall helplessly making him really open to attacks.
Final Smash:
Fierce Diety Link: Young Link turns into Fierce Deity Link. He's basically Link, only with longer range and bigger power, he's only able to do normal attacks, aerials, and Link's Up-B during this time limit.
In short, Young Link would be a slightly weaker Toon Link in terms of normal and aerial attacks, but has the better useful projectile games than the other Links, though his specials are much more riskier. This is something I could likely see happening.