You're all incredibly confident in Postecoglou's system, I see! Which is cool, by the way, I wish I were, too. I've got no opinion whatsoever: I've never seen his teams play, bar for a couple of Australia games when he was their manager.
I'm just going to point out that he never got that kind of stats anywhere he's played but maybe Postecoglou will turn him into a different player. I'd feel more confident with a proven goalscorer and Richarlison wide but I'm happy to be proved wrong, of course. Same thing for
@Bedfordspurs' comments that we will concede less: that remains to be seen because a higher line usually mean less chances for the opposition but with a higher goal percentage (that seems to be the case in the first couple of friendlies but I haven't actually seen the games, so...). Not sure the defenders we have are well-suited to that system too but, again, I guess we'll find out over the next few weeks.
To get back to Richarlison, he scored 1 goal in 27 games last season. If, for whatever reason, he can't do a lot better this term, it will be a very long season. EDIT: I checked and his stats with Brazil are much better: 6 goals in 8 games last season and 20 in 44 overall. So maybe there's a decent striker in him after all (or international football stats are meaningless).