Sure you could use the sun to sling shot you out of the solar system many times faster than voyage but we're still talking hundreds of years to move a fraction of a light year.

Exactly, and with modern advances, we could probably even get better initial velocity with the same fuel mass. Higher exhaust velocity from the same exhaust mass will get you higher total acceleration. Another factor is the duration of acceleration. And there are a couple of options we now have that can do that.

NASA has successfully used ion drives on interplanetary space craft. They use very little exhaust mass, but at such a high velocity and for such a long duration that it can provide useful propulsion. The DAWN spacecraft used ion drives which allowed it to be the first craft to make extended stays at two different celestial bodies, Vesta and Ceres.

NASA has also been experimenting with solar sails. These don't require you to carry any fuel for at least part of the flight. Once deployed, the sails get you constant if minimal acceleration from the solar wind. That minimal acceleration over a period of months can add up to a lot of velocity.

That higher initial velocity combined with a gravity assist, like Voyager used, and newer probes could conceivably overtake the Voyager probes in a few decades without necessarily using any more fuel mass and still be able to carry tools to do exciting science.