I would be flattered to receive any sort of fanart. I would actually love to receive art of a non-canonical pairing, because that means people are invested enough in the characters to care about whether they are together or not, and it means that I have characters that have good enough interactions to be considered shippable. That's writing goals, right there.
I imagine I might be a little squicked out if the pairing was really messed up. It would be uncomfortable to see fanart of an incestuous ship, for example, or one that fetishized a character to an unsettling degree. In the end, however, people are allowed to ship and do what they want to. I mean, I have a track record of writing canonical relationships that are seriously messed up because I find them interesting to explore, so who am I to judge what other people write or make art about?
I guess I tend to fall into the camp of, "You can do whatever you like, since once it leaves my hands you are free to interpret it however you see fit. I won't necessarily like what you do, but I will always be happy that you care enough about what I have created to put time into creating something of your own based on it."