Because Bergenheim is a better hockey player than Andersson in every single possible way. But also why that deal would not happen straight up.
For the record, I completely agree with you. I'm not even trying to say that it's a deal that could or ever would happen. I am just saying that given the type of team Detroit has, that would be among the only logical deals for a gritty forward, and I don't know if either team would be really all that interested. I don't think it's worth it for Holland to move Andersson + a pick or whatever just to bring in a bottom 6 forward that basically has played his way out of a team that is 3 points out of a playoff spot.
What other spot on the roster is available? Mainly just Andersson's spot, and maybe Jurco's spot. Miller, Glendening, Weiss, and whichever top 6 forward draws the unlucky hat tomorrow and ends up on the third line - they're all pretty much set in stone I'd imagine.
I don't think there would be interest in a guy like Bergenheim unless Florida decided to just basically give him away - and I think that was mainly the point I was trying to make. Trading him for Andersson would basically be giving him away.