In my opinion, Absolutely Not..
Blount is in a hard division but it being non ppr, who gives a shit.. Blount doesn't see much passes, but it doesn't matter. I would take Blount over forte for the simple fact that Blount is the work horse in TB. The Bear's signed Marion Barber, who people seem to think will have a break out season. I stayed away from Forte.. the Bears have NO W/R's and its simple to focus on Forte, plus he did not impress me last year at all.. I know a lot of people in my drafts felt the same, he went pretty late round.
Blount > Forte
Blount is more explosive and is good for more 100+ yard games.. Forte is slowing down and has no QB. If the Bears don't cut Chester Taylor, you have another back that will be in on 3rd down and goal lines.
as far as Colston/Welker I do have Colston on my Team, but I think they are equal.. both are on great teams with many WR options. Even though both are thought of the superstar WR's on each team, in my honest opinion Welker is more consistent..
People seem to forget Blount didn't start until Week 7! He had a MONSTER rookie year.. Blount all the way. No Brainer for me, if you make that trade you are definitely not getting the good end...