I keep going back and forth on this one. I'll try to type thoughts in here and come to a conclusion.
I think I'd rather own Koivu than Zetterberg going forward (one guy is gaining linemates, the other is losing a hall of fame puck moving d-man; both are band-aid boys). The fact is, Koivu has been a 70 point guy when healthy. It's close, and one guy has a few years on the other.
Staal is the huge wildcard. He could break out big time, but he hasn't done it yet.
Granlund is also a wildcard. Lots of hype, but he's already injured this year. A couple concussions in his past I think. And he's little. A bit scary. I'd opt for Staal in this one.
Going into this year, I'd probably choose Gardiner over Pitkanen. Pitkanen has some competition in Carolina, and he's had a tough time staying on the ice himself. Neither of these guys will probably be a keeper long term.
I suppose I'd take the chance. I think Staal has a bigger chance to be an impact player on your team this year, and has a bigger chance to fight for a keeper spot. The only way I see this hurting is if Staal stumbles and Koivu explodes. I just can't see you hanging on to either d-man at year's end, and I can't see Granlund forcing his way into your keeper discussion.
I'd start by proposing the deal without Zetterberg/Koivu. You'd have a better sense of your trading partner, but the offer seems like he's chasing youth. Gardiner and Granlund should be enough to get Staal, and getting Staal for those two feels a bit safer for me. I might even express my excitement for the youngsters, and push for a pick in that counter-offer, or another more established player that'll feel like a throw-in.
Just my two cents...
Points-only, Full Keeper Dynasty League
Active roster (no starts, just total points): 12 FW, 6 D, 1 Goalie
Forwards: Ovechkin, D. Sedin, Stastny, Nash, Kesler, Ribeiro, B. Richards, Selanne, Hossa, Fleischmann, Whitney, Lecavalier, Alfredsson, Okposo, Plekanec, Doan, S. Kostitsyn
Defense: Goligoski, Campbell, Gonchar, Bergeron, Liles, McBain, Vatanen, Timonen, Visnovsky, Giordano, Wideman
Goal: Luongo, Holtby