A good passing game requires 3x matchups that can win vs their counterparts. All the media go crazy over #1 wideouts but those guys (who can win 1 on 1 vs any corner) can't carry an offense in today's league because good secondaries can double and remove them for the most part. What can carry an offense is matchup advantages that go 3 deep.
GSoT is a perfect example of this. Faulk, Bruce, Holt, Hakim gave them 4 deep looks with those guys winning matchups vs their counterparts. Hakim wouldn't win vs a top corner, but you're not gonna put a top corner on him and he would eat up most slot corners.
So in answer to the OP any time you have emergence of a passing game threat it's a good thing for the offense. Higbee has emerged in large part due to Cooks' play falling off (as well as Goff's play incidentally and that of the OL at large), which has seen the Rams live off of short and intermediate routes moreso than last year. Gurley has also suffered in the passing game and probably due to his knee status, where the passing game requires more of that lateral movement and cutting he probably doesn't want to do.
So IMO right now the Rams have Kupp, Woods, and Higbee showing consistent wins in their matchups. Everett has potential to grow in that regard and so does Hendy but obviously that's a next year possibility. They're an average passing game offense with 3x matchups, a good one but not special and this is also due to the protections depending on extensive pocket movement and misdirection. If the Rams do nothing other than fix the line, that extra protection should translate into more potency and deep play potential but they're still going to be in the good not great range barring Cooks having a big bounceback season or JRey stepping up as a plus guy.