Would love to have Green. He is an excellent trigger on the PP, makes a nice first pass, and is (just) under 30. Not good defensively, and aside from Vlasic, who I want playing with Burns or Braun, we don't have someone who can support him. It would take acquiring another player to cover for him, which would be a pain in the ass.
If we move Burish, 4 of the 7 eldest Sharks will be gone (not counting Kearns), and the team will not likely replace them with players of an equivalent age- I don't consider Scott terribly relevant, even though he is roughly Burish's age.
Green replaces Boyle (Sharks get nine years younger)
Mueller replaces Stuart (Sharks get 15 years younger)
Tennyson replaces Hannan (Sharks get 11 years younger)
McGinn replaces Burish (Sharks get 8 years younger)
Niemi traded, replaced by a guy like Reimer (Sharks get 5 years younger)
Goldobin replaces Havlat (Sharks get 13 years younger)
Hamilton replaces Kennedy (Sharks get 5 years younger)
Obviously, not all these would happen this year, but these moves/similar ones make the team 66 years younger, an average of a little less than three years per player. Average age fromstats.nhlnumbers.com shows a spread of 30-26.5 (I dropped NJD- huge outlier). Those three years would drop a team from 2nd oldest to fourth youngest.