The most slam semis in a row might be difficult but it is not impossible. The mens game has NO depth outside the top 4 right now and for the forseeable future, no matter how much you hype Ferrer. Berdych and Tsonga are the only dangerous players, Berdych is his slave, and Tsonga has become his slave in the last several years. Another 3.5 years worth of slam semis of every slam? Definitely possible
I agree. Djokovic has been very consistent, and may very well continue to be. All it takes is one loss, though. It will be exciting in a couple years if he starts getting closer.