[PantherPrincess]

You can sort of do this already with destiny Mage (or whichever combination you want) and 50 Aptitude combined with high Will + the elements of your choosing + 2 Tomes. Which will ultimately give you good control of about 5 elements to 6-7. I don't think adding a tome that changes your starsign is really fair considering no one can just change it on a whim and this would make luminary element combined with this tome pretty much the go to mage build.