...if somebody wanted to do their homework, I'm sure they'd find that there were significantly more than 150 faces seen on that ship over the course of the series.
Well, the good old Voyager Roll Call page determined that all 150 people were accounted for by the seventh season, that is, 150 different names were used in the show, give or take a couple.
The much fuller, 200+ list at Memory Alpha takes into account "gag" names from Okudagrams that were not seen clearly, in addition to names from clearly seen graphics. Make of that what you will.
As for the number of faces seen, I have hard time believing they really went through a hundred extras in the seven years, in addition to speaking crew roles. But I guess it's possible.
Timo Saloniemi