This is very interesting to see. While I'm not against the idea of Female Link (that and because half of the fanbase would kill me for just having my thoughts that I don't care about Female Link), I really don't see this incarnation as her own separate character. After all, fans tend to consider Link some sort of avatar (though he's an established avatar no doubt) so I don't see how Female Link would be her own character. If anything this is probably a gender swap option that would be given to the player should he/she desire to play as Female Link. Considering that the concept still pertains to Link, I personally think that Female Link is a gender choice for Link and not a full fledged character such as Lana with a unique moveset.
Umm... as far as I'm aware, this female Link is purely a concept and doesn't indicate that female Link is playable in Hyrule Warriors. At the very least this proves that Nintendo gave the idea of putting female Link in Hyrule Warriors some thought.
Having said that, whether we will be able to play as female Link is still possible. Due to the nature of the story and how different characters come together, the idea of a female Link isn't weird. I don't really care much about female Link to be honest but if she does make it in the game I would understand, but at this point, accepting concept art as confirmation for a playable character is pretty farfetched.
Assuming this isn't a scrapped idea, I believe this would just be another costume for link. It's not farfetched to see several Link costumes. Especially when Luffy in the first Pirate Warriors' game had like, 9 costumes.
Very neat indeed. If this was a main installment then I would need some explanation for the gender switch, but to be frank, since this is a spin off, I'm all for it.
Even though Hyrule Warriors does seem a tad messy with the inclusion of several charterers from multiple eras (not sure how they going to execute the story, lol), I think it's good that they're going all out and going against the conventions so to say. Spin offs should be this way - they kind of act like a fan-fic's dream.
I hope that this is indeed just concept art. I've already stated that I am opposed to the idea of a female Link due to the further confusion among the general populace as to who Link is [I'd much rather Link be a solidly identifiable character that people can resonate with, and him always being male plays a large part in that]. Even if this is just a spinoff game and I don't usually care what they do with characters and whatnot, I still do not like this idea because it tampers with Link's identity.