Exactly how competitive are the 2 word searches? It may be that the new algo specifically targets very competitive searches. Generally speaking 3 word phrases aren't nearly as competitive. Not only may this be relevant if the algo is targeting based on competitiveness, but also that other webmasters usually aren't focusing on the 3 word or more search phrases. The required SEO skills to rank well for a 3 word search tend to be much lower than to pull it off for a competitive 2 word search. Thus if you try really hard for the 3 word searches, usually you can succeed.