Keith will cost more than that, probably like 2 2nds

2 reasons: Keith will be old as hell at 37, and he'll also cost too much for an old man.

I highly doubt that. No way he returns more than Arvidsson. Maybe a conditional 3rd that can become a 2nd.

Arvidsson was moved out of desperation because of the expansion. Keith should return more than Greene at least

Greene was an expiring UFA and did not come with a contract ending at 40 yo. He was also the league's top shorthanded defenseman the season before.

Greene was a bad trade, but whoever trades more than that for Keith is gonna make an even worse trade.

Hawks decline. We don't have any cap troubles. If we don't get okay value for Kieth we don't trade him

I agree with you both however I think the flat cap tax has to be accounted for, look at the recent contacts for Erikson Ek and RNH, both on less money than Keith. I think (1) 2nd is the best we would get or early 3rd. The teams he wants to go don't exactly have a ton of cap apart from SEA.

TBH I would prefer he stay, but I do respect that he has earned the right to decide where he wants to play after all he has given to this organisation.