Was it really important to continue with the Bourne trilogy that has attained a certain fandom over the last decade? Not really. Not considering the main players were all going to change.
The Bourne Legacy is more enjoyable if you look at it as a completely separate film. True, it tries to bank on the name of Bourne by running its story parallel to the third installment of the trilogy, but that is just a ploy to not having to explain the intricacies of the complex story (of the earlier films) and also a way to cash in on the trilogy. The annoying aspect of this, for the audience, is that if Bourne Legacy was totally detached from the earlier films and released under a different name, it would probably be exactly the same movie it is now.
So, Bourne Legacy runs like an average thriller. Having realized that it is not at parity with the earlier films within the first 15 minutes, I was able to enjoy it a whole lot more. It does have a simpler plot and Jeremy Renner's Aaron Cross might not have the same impact as Matt Damon's Jason Bourne, but he does manage to prove himself as a commendable action hero who just might carry the franchise on his shoulders.
Negatives aside, the film does work well as an action thriller. It's not as smart as the Bourne Trilogy, but is intelligent enough to rise above the average run-of-the-mill action film. Edward Norton and Rachel Weisz provide the necessary acting support to Renner's agent on the run and on the lookout for answers about the organization he works for.
The highlight of the film remains the climatic 20 odd minute chase through Manila. If you look at the big picture, the entire film is a chase movie, but the climax surpasses the hour and a half gone by before it. It might not have the big explosions and car crashes that are ever so present in Hollywood action films, but does have a certain in-your-face living-on-the-edge attitude that makes it all the more fun to watch.
The Bourne Legacy fails because by linking itself to the Bourne Trilogy is draws unnecessary comparison. It also ends rather abruptly hinting towards a sequel, which is surely not going to be as highly anticipated as this film. Still, the film makes for an entertaining watch and with a story that is simple to follow it's easier to enjoy it without wrecking the brain too much.