It's not like I'd freak out if they started selling it, but I think it's nice that they don't. The fantasy of MK seems more childlike; I don't see where alcohol would enhance that at all.
I'm not one of those people who think that alcohol is evil and that it would corrupt the park. It hasn't corrupted the other three.
I say no, because it was Walt's wish that the Magic Kingdom would not serve alcohol, and I like to honor Walt's perspective.
That said, I do buy drinks in the other parks and if drinks were sold at the MK I would probably buy a drink there, too. But, it's OK with me that drinks are not sold at the MK.