It was just seen as unimportant cheesy electronic dance music, like DJ Sammy - Sunlight. Or Sunclub - Splash. Or Alice Deejay - Better Off Alone. That sort of genre. It wasn't hammered by any trance deejay. Nor played as classic in that first decade.
Whether it's trance... or not... that's always a debate of course.
Paul van Dyk played it right before it blew up in popularity. Of course, once everyone knew about it, no reputable DJ played it again.
Sandstorm is unquestionably trance; more specifically, it is anthem trance. What do people think it is? Pop? Hard house? Euro-dance?