Yea, I just have always wondered. We tend to make the Jedi out to be the greatest fighters in the universe. I can think of examples such as when Han Solo gets the jump on Darth Vader over the Death Star and could have realistically finished Vader off if he had realized the importance of his target. There are multiple occasions where the Jedi have someone get the jump on them, especially order 66.
I also wonder if it could be a matter of rock paper scissors when it comes to a lot of these things. Smuggler generally seems to be the one that would fair the worst, but i dont think we give them enough credit. They make a living out of NOT getting caught. That and Vader was unable to sense them all in the Millennium Falcon.
I wonder if the Expanded Universe is partly at fault for the Jedi seeming to be unstoppable. In the movies they are clearly vulnerable. In a lot of the books they appear to be unstoppable warriors unless another Force user comes after them.
I think this was said during either the SW class quest or maybe just a throwaway quest that had lines for a Sith. But one of the Force-users in the Empire mentioned the Force beginning to weaken.
So it could be that during the ToR era Jedi and Sith were tiers above what have come later.