I don't want Dell, because he's too small.
However the 40 time is redundant, because he gets open almost immediately. I believe his 10 yard split is more important. As far as I'm aware, he was the most open receiver in college football against both man and zone, and in short, intermediate and deep routes. It's his suddeness, burst and change of direction that make him an intriguing prospect. At no point in a functioning offense are you going to want Tank Dell to sprint 40 yards down the field in a straight line.
Again, I wouldn't draft him because I don't think his body will be able to take the punishment but his 40 time is not a concern for me. He gets open. Same with Addison.