there's no way to prove the explanation for Robert's performance was simply "sophomore slump." and the reason is that NO ONE has explained what that means. Any data scientist will tell you: a statistical correlation is not an explanation. It simply highlights a pattern. It doesn't explain it. (you know - like "global warming"!!!) And unless you can explain it, you can't conclude this explains Robert's season. I'll stick to the no off-season preparations/rushed back hypothesis. I can't prove that either - but it makes a lot more sense to me than "well....it's happened to other guys."
the problem with the coaching explanation is that there is a counter-example: the 2012 season. we know he succeeded with the same coaches. what was the major differentiator between the 2012 and 2013 seasons?
in fact, I don't believe enough thought has gone into the overall "it was Kyle's poor decisions" line of thinking. Again, in terms of explanations, how do you establish this? what I saw was a QB who couldn't execute; an offensive line that couldn't pass protect at key times; a rb who did fumble; no real downfield threat in the passing game; receivers who sometimes got open..often did not get much separation; a QB who tucked and ran quickly quickly many times; lot of injuries in the receiving corps; lotta 3rd and longs; a defense and STs that got the offense into a hole early...again and again; routine dumb penalties (i.e., focus) at the wrong time; dropped passes.
it's not that Kyle didn't make poor play calls or drop the game strategy quickly - he did. but there was a lot of other stuff going on to definitively lay blame at his doorstep. He did well as the OC in Texas and, whether hired or not, it is telling that Ozzie Newsome has invited him back for a second interview.
in the event, the current meme is that it was all the Shanahan's fault. this is essentially what Allen and Snyder have been communicating. ok. let's move on.