Does Windclaw Shaman have a buff by default, or does the parenthetical text only apply when spending a buff to buff this card?

Ruling: Windclaw Shaman does not have a buff by default. You still have to spend a buff to buff and ready him.

Nuances:

• A unit can generally only get buffed once
• If a unit already has a buff, nothing happens when you try to buff it again