Yup, there have been threads on it, and afaik there isnt a mod to deal with it yet. I agree it is annoying and discourages dual-weild + spells for a pc user, since you have to pause the game to switch so you lose fluidity.
People are going to say just use the favorites menu, or pause the game for each switch, but that is a bad solution and they are not thinking it through. Doing a pause/switch once isnt bad... Doing it 500 times gets a little annoying.
Let the forums know if you find a solution.