Is there any way to only view reviews which need attention? For example, if I have review which to which I have added a defect, I don't want to look at the review again until the review either has new comments or new revisions.
There is currently no way of filtering reviews by comments - only by state. Your Crucible inbox will give you reviews that need to be reviewed or closed, however not those which have unattended comments. There is currently an open feature request to add support for this: CRUC-2938.