I've just found my access card to the suggested edits review queue, and find that there are a lot of low-rep retag edits in the queue thanks to this: Kill the Retag option, use just Edit
Now, as far as I understand, a retag is intended to only change the tags and as such at first glance will always seem a minor edit, but unless it is an outrageous suggestion, it is still a worthy edit and should be approved. However, I have noticed that most retag suggestions have at least one reject flags on it.
What is the right approach here? I have tended to approve most retag edits if they, like I said, were actually related to the question.