Well, it was a complete failure in that whatever consequences it had translated directly to the public, which is a big no-no if you are trying to further your research. It may or may not have had a big impact upon the storms -- and with so many factors influencing storm intensity (and track), many of which were not known back then, we may not truly ever know -- but did have a perceived negative impact on the public, making it a failure at least in that sense.

It might be worth it for someone down the line to go through the database of Stormfury storms, the cases in which known attempts were made to influence the intensity of the storms, and see if any definitive conclusions can be drawn knowing what we do now. There may not be a lot of support for that, though, given the general aversion to weather modification within the community.