in the end doesn't really matter what we call it, i think the main styles are quite evident, ie goa, full on, dark, prog etc
all sub genres of music are ultimatley created by media/marketing to sell it/ describe it to the people, think about other genres, when does drum n bass cease to be and become breaks/dub step etc
when does rock/hard rock become metal? to you metal heads death metal can be blured sometimes to say grindcore, as there are some bands that sit in the middle so how does it become defined, treat goa the same and this dilemma will go away, personally i pondered this for awhile then thought does it really matter?