If WR4 were not important, we wouldn't have them.
Interestingly enough, we even occasionally run 4 WR formations.
We will see, but it feels like we better hope we can win a lot of games 6-7 because of our DL, since our OC isn't exactly a mensa winner and guys like Darboh or Lawler might be on this team helping us to punt a little bit more often.
Edit: As for how Collins screwed us? Because we didn't keep a returner and he was supposedly on the roster to back up Rawls if Rawls was still injured (which he was). But not only could Collins not produce as a returner, he did nothing when we didn't have Rawls available - which killed drives and exhausted our defense.
Should we go back and look again at all the '2 Yards & a Cloud of What?' production that Collins brought us where an injured Wilson was facing consistently long yards to go? What about the long fields we had to drive for scores because our returners were essentially worthless, to the point we started using guys that should never be returning kicks?
Collins took a roster spot that a producing player would have had and he sucked up downs that a productive player should have gotten. Go back and watch the games to see how often using him shut down our offense and exhausted our defense.