I don't know - I am pretty big fan of mediocrity principle, yet here it is suggested that the reality might be different. I am still inclined to think that, with our current methods and technology, it's simply easier to detect big exoplanets close to their stars, or in highly elongated orbits, than the Earth-sized and smaller rocks somewhere inbetween. Oddity this article is talking about may be arising from there?
Also, idea of tumbling Jupiter sounds a bit crazy to me. Once the massive planet has been formed in protoplanetary disk, it should be extremely hard to move it around.