I made this for inspiration:
Why are his eyes like that?
To begin with, Young Link will have a Fierce Deity system inspired by Hyrule Warriors: As he deals damage, a magic meter, appearing in a similar location as Little Mac's KO Meter, will charge up.
Side Special - the classic boomering will have a buff, with a longer range, speed, and power,
Standard Special - with the buff of the boomerang, there'll be less of a need for a bow and arrow... Which will be replaced by something inspired by Hyrule Warriors. Young Link would play his Ocarina. This would boost his magic meter, depending on how high his damage percentage is. The higher the damage, the greater the boost.
Up special - ain't nothin' different.
Down special - instead of an ordinary explosive, I'd like to see the powder keg appear, with similarities with to the Blast Box, but more volatile. Of course, I'm not much of a Young Link/Toon Link/Link main, so I'm no expert on whether or not this is a good idea.
The shield will be moved to Link's bag, slightly more vulnerability. His Ocarina will be left in his right hand.
The first taunt will be milk, obviously, the second should be Young Link equipping the mask slapped onto the side of his head. Don't care about the others.
I would also like to see some variety with the costumes and palette swaps:
Green - has the Deku Mask,
Red - has the Goron Mask,
Blue - has the Zora Mask,
White - has the Mask of Truth,
Black - has the All-Nights Mask,
Purple, blue hair - has a blue scarf and a rabbit hat,
Dark Green, darker hair - no mask, Deku Shield and classic Kokiri Sword, inspired by Ocarina of Time,
Something involving the Gilded Sword and the sad Mirror shield
I'm mostly just brainstorming here, but I think these changes are subtle enough to satisfy old Young Link fans, while keeping him different from Toon Link.
While he's in Fierce Deity form, he would handle most moves easier, throwing the giant bombs easily, having greater range,
his side special would switch to the ball and chain, which would function like a buffed boomerang. (That was a bad idea.) He would be harder to launch.
His Final Smash could be Chateau Romani, turning li'l Toon Link to Fierce Deity again, using the sword beams ever so loved.