There are acouple of mid tier WR I think he will target instead.
Like you pointed out with Carlson, over paying in free agency often results in cap space money wasted. It can have a negative affect on the team for the future and historicly doesn't pay off.
Rarely does bringing in one player have a huge impact on a team.
Favre as an example, had a huge positive impact one year and a negative impact the next. In addition his cap hit reduced the Vikings ability to be much of a player in the free agent market for a couple of years.
I would like to see Wallace in purple, but realize he probably isn't worth the money. Better look for a speedster in the draft.