I don't know why there is a check for a double slash.
I understand why someone might want a check for an ending slash, but I haven't found it useful. I think what that rule wants to say is "end with a slash, or be blank", so that is probably best written as (|/)$ (I didn't test that, because again, I don't find that rule useful) I think raymor's analysis of ![^/]$ is fine too, I don't know performance-wise if one is better than the other.
Yes, I don't know what the HTTP:Profile is, I removed it.
For the query string, as far as I can tell, it just saying QUERY_STRING contains an equal sign, and so is a long way of saying !=, and so the new rule is better than the original, but I think you are saying that you see a difference in the two rules?