There she is! Amazing. I was hoping to see her finally in the Direct and Koei Tecmo again listened to the fans! They made Linkle a thing and she looks lovely. Overall Koei Tecmo did a great job with their original characters, so I'm not worried at all about this.
It would even be nice to have her as an option in Zelda U. And why not? Since the game seems to have a huge focus on the Bow, she might be a nice fit.
By now we got five new characters for Hyrule Warriors Legends. I think that they may want to have six in total, as many as there were added to the original game via DLC and updates. And Toon Ganondorf is probably the most likely candidate here, next to Toon Zelda. Maybe both.
I still would like to see Nabooru, the Deku Princess, Mikau, Yeto, Groose and Batreaux in the future, but they don't strike me as important. Maybe Groose though, Skyward Sword could really use another good character for their team and he was already dearly missed in the original, since it would have made quite some sense to have him there.
So, I think it's going to be Groose or one or two more toon characters.