Are the D-backs changes enough?

Let's compare the 2013 Opening Day roster with the likely 2014 one, at the current point in time.

For ease of viewing, I've mostly matched up players in 2013 and 2014, regardless of role in the latter, and I've bolded and italicized the spots on the 25-man roster where there appears likely to be a change. There's still uncertainty about the backup catcher spot. This also assumes Ross will be on the DL. Conveniently, he was in 2013 too. :)

What strikes me is how similar the team is likely to be, particularly in terms of an everyday starting line-up [six of eight return] and the starting pitching [four of five will be back]. The changes will mostly be on the bench and at the back of the bullpen. Considering this is a team which finished eleven games back in the division and nine games behind the second wild-card spot, will these be enough to allow the team to make up ground? There are some spots where there should be improvement. Even the most skeptical would admit Trumbo will be an improvement over Kubel, and whoever replaces Kennedy - be it Bradley or a free-agent - could give us some help too.

However, most of the other positions appear to me, more or less, to be a shuffling of the deck with limited upside, e.g. Thatcher for Reynolds, Gregorius for Pennington, Campana for Marte, etc. It seems that the team are relying instead on improvement - or, at least, a return to expected form - from those already on the roster. The three names in particular who come to mind are Miguel Montero (2013 OPS+ 83, career 105), Brandon McCarthy (2013 ERA+ 84, career 104), and Trevor Cahill (2013 ERA+ 96, career 105). Good health, giving us a full season of Aaron Hill, would also help, and if Cody Ross returns to productive health, it'd be no bad thing.

Is it going to be sufficient? How many wins would you project from the current D-backs roster? What more is there that they could do? Discuss...