Why is Each Cygnus a Cygnus?

You know, it actually did start as a volcanic eruption back in kMST, where a volcano would rise behind the F/P AM instead of the circles we have now. The icon was different too and showed the volcano. Not sure why it was changed though.

Maybe it was "too complex" or too graphics heavy. Perhaps they decided it was too much earth, or it didn't match with other mage skills appearing from thin air (not as "magical")