I think a different kind of art direction than the one in Wind Waker could do wonders for the series. Maybe something that resembled an oil painting, something Baroque/Rococo inspired (that's Baroque as in the 18th century art style, not the game), for example. I guess my issue with Wind Waker's art direction was that it was too radical a change while many other design concepts didn't evolve much from OoT/MM. It was like Nintendo missed the point. People lashed out at the graphics for being "not Zelda," which I agreed with to a point back then (now, it's just an accepted fact) but I found it charming enough that the same art direction could have been applied to a completely new and original series not tied to the rules and confines of the Zelda series and been one of that game's main selling points, the thing that made it stand out, rather than a Zelda game that alienated some fans. In other words, the Zelda brand was used to sell the art direction rather than the art direction selling the game.
My hope, though, for any sequel, not just for Zelda, is that the developers learn from mistakes made in previous installments. Twilight Princess seemed to be a response to people's distaste for Wind Waker, but many things remained largely unchanged. There was still a very large open main hub world with almost nothing to do. That was true over 10 years ago with Ocarina of Time and was still true in 2006.
I don't want to judge the new Zelda based on one fuzzy pic of concept art. However, making Link older doesn't inherently change anything.