I think most people think the offense sucked because of the postseason shortcomings. I'm hoping the postseason offense will come around with experience. They just seemed so uptight and overaggressive against Giants.
I think it is also an issue with what appeared to be too much reliance upon the long ball to score runs and a lack of situational hitting - both of which tend to be a negative in the post season and remain as the biggest knock on this team's offense. Even excluding the postseason, the difference between those general stats and the same ones with RISP and RISP with two outs tells a different story. They were a lot worse with RISP and their AVG with RISP and two outs was last in the NL - very telling.
Some of that in 2014 can be blamed in part due to the loss of certain guys to the DL. Espinosa and Lobaton were black holes for large stretches of the season, and Desmond and LaRoche's all or nothing approach led to a lot of streakiness. 2013 was historically bad in terms of PHing. The team was killed by the combo of an all or nothing lineup and a dreadful bench that were automatic outs when they needed contact. Minor improvements to the bench last year coupled with the injection of Rendon as an everyday player helped improve the balance compared to 2013. But it still wasn't enough. I hope that with RZ back in 2015 and LaRoche gone, that we will see even more balance given some additional maturity in Harper and Rendon. Espinosa brings the whole offense down when batting left-handed, so they need to avoid that altogether. Getting a well-constructed bench with guys who make contact, understand situations, and don't strike out all the time will be critical to keeping the offense alive.
They need to take advantage of the RISP. The stats you quote are fine to keep as is, if they can get similar numbers with RISP. That would be a huge accomplishment.