Rootski,
I have found that these baits work in both lakes and rivers. I think a big part of it is confidence. I have become a lot more successful with swim jigs on the lakes around Madison, Wisconsin than when I first started using them there. Part of it is learning over again how to fish these baits in different conditions. I also learned to swim jigs on the Miss.
If you were to have found the right combination of size/color/presentation, you would have probably loaded up on bass in those areas you were fishing. Sometimes for me it is as simple as changing the color of the jigs, or trailers. One thing for sure is that no mater where, or when I fish in the year, I always have a swim jig tied on. They can be just too deadly not to.
As far as the rubber worms go, I often catch walleyes from both rivers and lakes while jig worming. If you think about it, a rubber worm is nothing other than an extended grub.
I am sure others will also chime in with there thoughts, but if one bait catches fish for me in lakes, I would at least give it some serious consideration in rivers,if the conditions warrant it.
Just my thoughts
Bassman