How important do you think Toon Link and the whole Toon Zelda style is to Nintendo as a whole?
Increasingly less-so, but I think it's a very significant part of Zelda's overall history. It seems like it's taken a backseat for now in favor of the "Toy" style, not sure if it's a permanent retirement or just a break for this generation. I'm honestly assuming Wind Waker HD will get a port sooner or later, so if that happens I suppose we can expect to see Toon Link at the forefront for a little while again.
I hope they aren't done making Toon-styled games forever, but they had a really substantial run. Enough to keep him safe for Smash? Not entirely sure, but I do have an itching feeling that some kind of green tunic-ed Link is important enough to have around. Unless next game goes harder on alternate costumes and lets Link dress up like his old self - if we aren't so fortunate, I think Toon Link is in decent standing.