The system last year was basically we put 3 midfield (cabaye, tiote, jonas) to protect the defense line, and use the direct approach to utilize our strikers' clinical finishing and prevent counter attack. This system worked last season because the key players were always available. We got huge luck in having most of them free from injury. The result proved that this system "worked".
Not saying that we should continue this formula this season, but I just want to emphasize that this system hugely depends on the availability of those key players which are not ALL available this season. As a result the defense line completely collapsed. On the other hand, this system wont bring us enough goals to cover up the goals conceded and that's why where we are now.