Is the spring tension too high the entire way, or is the lock just sticking at the end of it's travel?
Although I've never had it, some people do experience lock stick with compression locks. I could especially see how it could happen with a DLC coating.
I would disassemble the knife, throughly clean the locking surfaces, then rub some Sharpie permanent marker on them and see if you have an easier time unlocking the thing after that.
I would do this first because modifying the lock bar tension itself changes both your centering and your detent strength. Such consequences should only be had if there really is a problem. And if there really is a big problem with the lockbar tension, I would take advantage of Spyderco's warranty to see what they think of it.
