I am surprised it was never done in the original game, especially with how money hungry they were at the end, could have made a fortune if they offered it!
I'm not surprised it wasn't done, because it's a bad idea.
It isn't a BAD idea...
It is a bad idea, at least the once per character aspect. Changing primary/secondary sets would open up its own can of worms, but the people who make the threads suggesting it almost always include the proviso that it can only be done once, as if that improves the suggestion, when it actually makes it much, much worse. People would use their one change, switch to something they also end up not liking, and end up in exactly the same situation.