Personally, I'm all for uncombining them because they you could actually get certain magics easier. But, I just don't think it'd ever happen. I mean, it does pop up with a warning when you combine them. Having an uncombining option would make the warning null. If they never put the warning on there to begin with I'm sure we'd get the uncombining option eventually, but with it I think it's kind of like we warned you, stick with it now kind of deal.