Problem with the guys you listed. All are inconsistent and display poor hands a lot of the time. There have been tons of Height-Weight-Speed guys who failed in the league because they couldn't do one thing, catch the ball consistently.
That's why Ted Ginn isn't a great WR.
Donnie Avery is no better than a #3 WR.
DHB is no better than a #3-4 and is at best a decoy at this point of his career.
Stephen Hill has sucked.
And the list goes on and on. Lots of speed and size is great, but it doesn't matter if they can't catch consistently and use their size to dominate.
Unfortunately, from what I've seen of them. Janis, Bryant, Moncrief, and Enunwa all currently fall in the DHB, Avery, DHB, etc. category.
I love speed and size in a prospect as much or more than anybody else, but I still wouldn't draft the guys you listed any higher than the 3rd (Moncreif & Bryant) or later.