I'm a "while I'm in there" kind of guy. So I say that while you're messing about with the mechanism already, go ahead and pull it all apart, remove the latch assemblies, and clean them up good. Then re-lube them.
At the very least, check them out. Usually they're much more gummed up than people realize. Thinking normally, that Bronco doors are always hard to open. When in fact, if you have a good working set of clean and lubricated door latches, they should open and close like any other vehicle.
Excluding any trouble you might already have with door seals, which make closing hard no matter how good your latches are1
Paul