We don't know if Wallace is easy to replace but the main reason Wallace is successful is due to Ben extending plays. We have no idea if Wallace can perform in Miami with Tannehill throwing to him. Hell, even if you put him on a team with Manning, Brees or Rodgers it's a toss up. Can Wallace catch passes in traffic while draped? Can he catch timing patterns where Manning has the ball in the air before he breaks?
His strength is the go route and unless he gets with a QB who has the perfect pass I think we are going to see Wallace turn into a Nate Washington. A decent WR on a scrub team.
He will probably be overpaid by somebody, but the offense will be worse without him. Perhaps that can be helped through the draft, but that then precludes the team from addressing another area.
His time has been reported as being fake, although he did run in the 4.3 range.
We can't keep Wallace. He doesn't play defense.
Steelers 2014 Draft
1-Darqueze Dennard CB Michigan State
2-Jordan Matthews WR Vanderbilt
3-Jordan Tripp ILB/OLB Montana
4-Christian Jones ILB Florida State
5-Brent Urban DE Virginia
5-Michael Schofield OG/OT Michigan
6-Kadeem Edwards OG Tennessee State
6-Ben Gardner DE Stanford
7-Aaron Colvin CB Oklahoma
That being said, this kid is still super fast. Plus, the music playing in that video was really quality and not just a bunch of complete noise and trash.