Sure, I get that. But, for the most part, there are very few films that become significant blockbuster franchises.
And, when did we all become stock holders? What's wrong with making a standalone movie based on a significant storyline in the history of the medium and being done with it? Not everything has to be a trilogy. Heck, there is plenty of complaining about the quality of sequels all over. As a consumer, I'd rather have a good V For Vendetta than FF2.
Heck, there's the possibility that Watchmen will turn out to be the best superhero movie yet. I'll take that over a half dozen "franchises" that likely won't be anything special.