Without the main hero headlining the sequel it might be construed as a huge Hollywood cash-grab. And to all who think so... you're absolutely right. Hollywood reminds us once again that you can never have too much of a "good thing."
What I liked about Legacy is the story is mingled in with the Bourne Ultimatum story-line, where Jason Bourne finally exposes the shadowy figures behind Blackbrier and Treadstone - the secret military programs that turned him from a simple soldier into a killing machine.
Director Tony Gilroy, one of the writers for the previous three Bournes, does a sound job here. I actually enjoyed the film. It doesn't plunge headlong into action, but instead takes its time to introduce its newest hero, Aaron Cross (Jeremy Renner). Runner and doctor/scientist (played by Rachel Weisz), make a great team as two hunted souls who initially need each other for utilitarian reasons. While this movie isn't nearly as good as the first three films (duh) - there wasn't any cool "ah-ha" moments like Legacy's predecessors - the story still moves at a fast paste, the locations are stylishly shot and the action sequences are well executed, sans the finale motorbike chase scene on the streets of Manila. What was that?! That scene could have easily been cut in half or scraped altogether.
I'm sure they will continue the story a few years from now, and when they do I hope they bring back its star player. I could easily see Cross and Bourne teaming up. Wouldn't that be something?!