While I agree to a point, I know people that have read Watchmen with no comic background beyond the very basics and still seen it as an amazing work. Much is made of how Watchmen is a comment on comics themselves, which it is, but understanding that isn't necessary to appreciating the work.
I also in no way buy the argument that Watchmen is 'out of its time' and about the present. By that logic, even reading it now is foolish because you can't possibly understand it. You STILL have to understand the history to get a lot of the concepts when you read it just as much as if its in film format.
In fact, the farther I got through that article the more it just sounds like a rant about why it can't be done in a 'because I said so' arguement. Its almost complete assumption.
To me, a lot of the best parts of Watchmen are the characters and how the act so much differently than 'typical' superheros. In fact, that's what makes it such an amazing story to me. The way classic superhero concepts are handled are done amazingly, too. Both of those things can be appreciated by the general public these days. Why? Well, they aren't exclusive to comics. EVERYONE knows the basic idea of the classic superheros, especially with the movies that have been coming out in the last few years. So these kinds of commentaries that the characters all are can be seen just as much thanks to that.
And really, Alan Moore is Alan Moore. His work is amazing, but no matter how good a movie could be he won't like it. I can't say I blame him, but at the same time I do wish he was a bit more open to it. But, again, its Alan Moore, and he has good reason to be against films of his movies. But unlike the other works of his being turned into movies, this one looks like it might just be done right. Finally.