The other series is Mario though, with one of those being an Echo as well that has animation differences.
Seriously, Ganondorf got about as much work as Daisy did, so I don't really see how Zelda got shafted when it got the most love of any returning series that also didn't get a new character on the character select screen since it brought back Young Link, redesigned Ganondorf, tuned Link quite a bit with a redesign, and gave new aesthetic designs to Zelda and Shiek, while also making Zelda probably the best she has ever been solo. It was also one of two new first party bosses with the absolutely awesome Ganon fight (the other being Marx of course). And then we also got Great Bay, Gerudo Valley, and Spirit Train in HD; which means that every Zelda stage across franchise history is actually in this game and we got a new Great Plateau Tower stage to boot.
I mean, sure, something like Donkey Kong got King K. Rool and a new assist trophy in Klaptrap, but it also lost the Jungle Hijinx stage and Rumble Falls is still missing alongside the fact that Donkey Kong and Diddy Kong didn't really change much outside of final smashes.
I feel like you're focusing way too much on the character select screen considering Zelda as a franchise still got tons of love in Ultimate and still has beyond characters through Smash Brawl and Smash 4.