doesn't mean the guy who was more highly recruited is going to be better than him. Lassiter has proven to be a revelation for BYU. He will be very difficult to replace.
Roberts is the heart and soul of this team in my opinion. The reliable RM that puts in the work and keeps putting up results.
Will BYU be OK? Sure. Marion, Kingston, Hagen after a year+ back, Phillips, Epps (assuming he is still here), Nacua, Domonique McKenzie, and Lamason Waller to name a few off the top of my head.
That being said, I don't think they will have two WRs as reliable as Roberts and Lassiter.