The ineffectiveness of the Norden is overstated, since that's the trendy thing to do right now.
Admittedly, the Norden did not live up to its hype. Almost nothing performs as well in real life as it does under perfect conditions- this is commonly seen when going from the "golden testers" in development that graduated from test pilot school to the "regular testers" during operational test. But once appropriate tactics were developed (this takes a while with all new technology) and they found a few bombardiers good enough to lead bombing formations, it was effective. Not at the level of pinpoint accuracy, but the performance improved quite a bit over the 1943 results. They never took the Norden off the B-17s because any time the Norden had bad results any previous technology would have been worse.
To the point of my prior comment, Naval Surface Warfare Center Dahlgren, the place that is working on the USN's railguns, is the same place where they were able to get Carl Norden's design into a production ready state where 90,000 of them could be made with the precision of a master Swiss watchmaker. Dahlgren isn't staffed by a bunch of software devs that call themselves "engineers" because they think it sounds better. They have real engineers working on solutions to their problems, and a history to back it up. While you can't assume they've looked at every possible idea, they have considered many novel ways to fix the main issues of railguns.