It has been argued, notably by art-activist group the
Guerrilla Girls, that the second definition of 'seminal' below is a little on the sexist side, associating as it does all truly original or influential creative work with
maleness. In any case, it's certainly a tired-out word that seems to appear in every review of any cultural work that anyone likes.
The GGs recommend using germinal as an alternative, at least every now and then, and, as I was surprised to find, Webster's seems to agree that the two terms are equivalent for this purpose. It's still a gender-bound word, though. Many academic types seem to like the word radical for purposes of discussing the roots of things - that word's getting a bit overloaded, though. Maybe primary?