I was/am thinking similar.
OBJ and Woods are coming off ACLs and are no longer young. OBJ in fact has torn the same ACL twice now, if it is torn again. Jefferson seems to be a JAG - good in a depth role but incapable of stepping up or making the hard catches. Benny Skow should not be getting any snaps. The Tutu pick seems to be a total waste but it is still early and hopefully he proves useful (I am sceptical though).
I would not say there is cause for concern, necessarily, as Kupp and Woods are an elite duo. And if we bring back OBJ, the Rams' WRs are the NFL's best as far as I am concerned. But it would be a group that is very fragile. Even Kupp has been injury prone prior to this season. You'd definitely be walking on egg shells that the health could fail at any moment and the house of cards comes crashing down.
Lots of people are high on Harris. We force fed him in pre-season and his catch % was weak. He is so raw though, that he might well improve and become a serious weapon yet. And even Harris now has injury concerns!