Hey, I've played the GR shaman, and came to the conclusion that I could have just played a druid. If they are in love with the idea of a a shaman, allow them to take the spirit feats, or even perhaps the skills (2 of the 4 new skills I like). It is more of a matter about how the DM chooses to run the druid, rather than the exact "class" he is.
~~Brandon
~~Brandon