In answer to the topic title, I say; No, you don't.

In general answer, the adventurer in need is neither a tank, nor healer reward. It is a reward designed to incentivize players to run duty finder content in which ever role is currently in most demand. The fact that it's almost always tank, and if not then healer, reflects the relative scarcity of those roles. If you have a problem with that, play one yourself.