Columbus is happy with its 2-4 centers. Plekanec obviously brings excellent 2-way play and can provide secondary offense (we can leave concerns about his age and start to the season out). Montreal should value this, but because Columbus currently has Wennberg, Dubinsky, and Karlsson, I don't think they do.
Wennberg currently has 1-6-7 in 7 games. That's great, but I think his play puts him more at a 15-45-60 type player this season (most of his production occurs on the powerplay).
Columbus is looking for a center that pushes Wennberg (again, projected as 60 points) to the second line. That means a center who will likely score more than 60. That means probably a top-30 center in the league this season.
Nobody wants to trade a top-30 center. But that's really all Columbus is lacking and is really the only motive to swing a sizeable trade. Otherwise, happy with our wingers (Saad, Jenner, Atkinson, Foligno is rebounding, Hartnell is still strong, Anderson, Calvert, and prospects). Happy with our defense (Jones is great, Werenski is great, Murray is injured again, Savard is very good, Johnson has been remarkably strong this season, Prout is a goon, Nutivaara is a nice PMD prospect). Bobrovsky has rebounded better than anybody could have hoped (healthy and stealing games, 2 shutouts so far this season). Plus we have Forsberg and Korpisalo as goalie prospects.