Keenan Allen timed at 4.77 which isn't close to what he actually runs. Allen was hurt when he was timed. When he fully recovered his training improved his time and he runs in the upper 4.5 to 4.6 range. I know because I was there where the team timed him at a TC session for some reporters. But regardless he's like Kupp and Jefferson who also are nightmares to cover because of their route running. Kupp also timed at 4.7 before the draft. But after his injury, his rehab actually has made him much faster and quicker.
You also need to note that Jefferson timed in the mid 4.5 range by his coaches in college last summer. He has no official NFL times because of his foot injury. That is fast for a man his size. Florida looked at him as not only a mid-range threat but a deep threat as well. In reality, we also might be looking at another Robert Woods. They are about the same height and run with similar speed. The difference is Jefferson is more elusive in his route running. Jefferson is fast, with good height, good hands, who runs outstanding routes. He can run the entire route tree short to deep.
IMO the Rams now have one of the best trio of WRs in the NFL. So although I speak of a ball control offense, that quick deep strike element is still there and it's not just Woods. Out of their standard 11 personnel, McVay can layer his receivers as he loves doing. TE Everett short, Kupp midrange with both Woods and Jefferson going deep. Also, remember Goff will have Henderson or Akers in the flats. You blitz Goff now and you will get burned. With that type of passing threat the Ram draw or interior power run game will be very dangerous.
I think we are going to see an offense better than the 2018 version. People are going to be surprised because IMO the RAMS ARE BACK, watch out NFL because you have been put on notice. They will have a top 10 offense and defense this year. Also, this team is built for the long term.