Oak Sage or Carrion vine for PVM wind druid?

[ShadowHM]

Oak sage, OTOH, is a very useful spirit for both you and your party.  It'll also die a lot, but the extra life benefits from more points are very noticeable.

I do not understand why, but the Oak Sage spirit seems to have a huge 'threat factor' (for lack of a better term) to monsters.

My Oak Sage can be right beside my Druid and the monsters will target it before they target him. So the Oak Sage dies a lot. However, the Druid does not, because I have time to retreat and re-cast. :)

adeyke, is there some reason why Oak Sage has this high 'threat factor'?