I kind of hate that we never got Ganon in Smash as playable. Ganondorf, when he was added, had been in only one game (whereas Ganon had been in all five Zeldas up to that point if we count his Zelda 2 appearance). In fact, even now, Ganondorf's really only made 3 appearances in the mainline series (4 with Hyrule Warriors), while Ganon's track record ranks in the double digits. He'd have an amazing moveset, too! It should've always been Ganon!!
I'd love to see a Lynel, too. Why not? They've been around since the beginning, have appeared in more Zelda games than any of the Zelda Smash roster besides (adult) Link and Zelda, and are once again relevant and feared thanks to BotW. And now that we have Piranha Plant as a common enemy, there's really nothing holding back Lynel except perhaps an awkward body shape.
Otherwise, Impa is long overdue. She's a legacy character, recognizable and has a move-set basically ready to go. She could even rep Hyrule Warriors.
That's three characters who've all been around since the first Zelda, have strong moveset potential and have made at least 5 appearances apiece in the series. It doesn't just have to be one-offs to pick from (although one-offs don't seem to be a problem for other series, like perennial whipping boy Fire Emblem). Let's get more Zelda characters in Smash already!
I will say this, the stage selection for Zelda has always been great. Every 3D game is represented (OoT twice), plus Spirit Tracks and whatever Temple is supposed to be.