That doesnt make him useless, that makes him 4th and 5th round value. Find a wr in the draft with the same skill set that late in the draft. He will still produce. His stats dont show it because he hardly played on my team. People expect all players to have great skills in order for them to be valuable to anyone else so trading them for late round picks dont make sense, now if this was for a 3rd rounder I could see your point in saying it was a steal but these are mid to late round draft picks who may or may not even make my team.
Someone elses trash could be someone elses treasure. I have had WR with skill sets like this tear my defenses up before in games, maybe not for huge breakaway gains but nice short to middle catches.