Uhh...WESG? EnVyUs won WESG last year, the 2017 WESG hasn't even started yet. Besides, it's unfair to count WESG, because FaZe can't even participate in it. Are you braindead?
G2 has won EPL, DH Tours, and DH Masters Malmö in 2017. At DH Tours, the only decent opponent they had was...I dunno, HellRaisers, maybe, at BEST? Mousesports? Maybe nV? That's literally, like, mid-T2 competition at best. The EPL win was fine, and so was Malmö. They did good at both, and defeated a ton of good competition. So that's 3 events, 2 of which had decent competition.
FaZe won StarSeries season 3, ESL One NY 2017 and the ELEAGUE Premier 2017. The two teams have an equal amount of wins, and FaZe had more dominant wins at the events they won (and have generally been placing better than G2 throughout the year, with the exception of the major, where, well...G2 got 9th-11th place, so not THAT much better than FaZe).