The idea that a breaking wave is going to be coming from a significantly different direction is a crock of sH!T. From what I've read, a lot of study has been done on this and it just doesn't happen. Don Jordan mentions this in some of his writings, and that's one reason the JSD works as well as it does, since it helps protects the boat from breaking wave strikes.
I've read Jordon's assertions that this doesn't happen, but I've wondered if that only takes into account straight-forward scenarios where a single storm progresses through an area in a fairly uniform direction. How about cases where storms have made sharp directional changes (some have even back-tracked on their own path) or where multiple storms have passed through an area from different directions in a short span of time, causing dangerously confused seas? Concerning sailing south of the equator, I've also read of cases of very large swells travelling up from the southern ocean and interacting with storm-tossed seas from a different direction to make them even more dangerous.
It's clear that Jordon did a lot to further the science on this issue and the series drogue has proven itself to be a very valuable device for storm management. Still, I'm a little skeptical about placing complete faith in any one engineer's theories, test results, and solutions. We could use a lot more of his systematic, thoughtful, and engineering-discipline based approach.