This team is becoming a "run first offense". Smash mouth football. Now that is not to say that they will run more than pass, but you understand the term.
That being said, a deep and diverse receiving corp is not as necessary.
If you look at ONLY the receivers, then I think you are short changing the analysis. CLEARLY Witten is the #2 target here. So there is less of a need for a #2 receiver in this offense. Then you have the coming of Zeke that will be a monster in the passing game. I expect him to catch 80 or more passes this year. Another factor in needing less of a receiving corps.
Then you factor in that we have a top 5 WR in the NFL. And to me, this is THE most important thing in pass catchers. So we are better than 27 other teams in that regard. I also feel Beasley is a very good #3 slot guy. You want to complain that Williams is an average at best #2 receiver no issue there. "pass catchers" overall, this team has plenty for the type of offense we current have. You want to get into who we have past Dez, Beasley, and Williams, I really have much bigger fish to fry. Like on the defensive side of the ball where we almost need half the players overhauled.