I would be ecstatic. I've always wanted Link to be a girl, and it wouldn't ruin the character image at all. To most, he's a silent hero who has a sword and wears green. Not much indication that he *has* to be a boy, besides the fact that hero is masculine by default (heroine for females).
Nothing would change. Totally inb4 Zelda would have to be a boy. She doesn't.
The fundamentals of a Zelda are NOT "Link saves the princess". Did Majora's Mask do that? Nope. How about OoX? Nope, at least not Linked game and even then that wasn't the focal point. Did Link's Awakening? Twilight Princess? Nope, yes sort of but that wasn't the focal point of the game. The fundamentals of a Zelda game are simply great gameplay. Changing the gender of the avatar does not change a thing. Need proof? Look at Kingdom Hearts (wow, I use KH a lot). In KH1, we play as Sora. In KH2, Sora again (Riku and Mickey are playable momentarily). But fastforward to KHBBS. We get to play as Terra (a boy), Ventus (a boy)...and Aqua, who incidentally is a girl. It didn't change a THING as to what KH was.
This would translate over to a Zelda game. Link being female wouldn't change anything but his gender. It isn't as radical a change as, say, voice acting, and even that wouldn't automatically harm the game it is featured in.
Everyone hates/opposes the idea of Link being female, and I honestly ask "Why?". What seriously would change? The 3D animation would have boob physics [I don't agree with the whole "children shouldn't see the animation" because it is 100% natural for breasts to move according to how physics work], but what else would seriously change? The Link entity would have the same personality as the male Link. Link and Zelda isn't even an official pairing; not even the closest we got to official ZeLink (SS) confirmed the two as locked in love. They were, as far as we could tell, the best of childhood friends and nothing more.