I do see some good comments by users. Should up-votes on comments award some reputation (maybe 1 or 2 points)?
- Requesting clarification from the author
- Leaving constructive criticism that guides the author in improving the post
- Adding relevant but minor or transient information to a post (for example, a link to a related question, or an alert to the author that the question has been updated)
Getting reputation for asking a clarification is not what I would want, considering that:
- There is no way to down-vote a comment
- Comments are generally ephemeral
The effect of giving reputation for up-votes on comments would be just to make users write comments with the hope to get up-voted, and extra reputation.