As I noted in the Change Original Referrer field type from text to text area idea in June 2012, the Original Referrer field
truncates at 255 characters. Unfortunately many referrer URLs are much longer than this and valuable query parameter data is lost in the Original Referrer field. The solution I proposed was to change the field type to a text area to preserve this data, but the idea's Status is "We Like It, But It's Complicated" and this idea may not be implemented for some time, if ever.
A workable alternative would be to create an Original Query Parameters field that would hold just the query parameters. If this is implemented, it would be great to have the ability to retroactively populate this with the Query Parameters that were captured in the first website visit.