A lot can change in one year actually:
1. Gattis proved he wasn't a long term option at catcher therefore severely minimizing his value to a NL team.
2. BJ UPton followed a historically awful season with another awful season.
3. Chris Johnson was inexplicably extended and has a terrible season
4. Mike Minor has an injury issue that questions just how reliable he will be in the future
5. No prospect emerges as a legit second base candidate
6. Essentially everyone on the farm takes a step backwards aside from Peraza/Albies
7. The 2013 draft shows itself to so far being an absolute joke
Yes, a lot can change in just one season to make the future of a once promising franchise look very bleak unless specific actions are taken.
I think a lot of those are just excuses. Johnson isn't as bad as he was in 2014 and not as good as he was in 2015. I think any reasonable person could see that. And a platoon would fix that position instantly. La Stella did emerge as a 2b option until Peraza or other long term options emerged. BJ is crap and most epected that to cotinue.
There are those that think 2014 was just a bad season and that 2015 would have been closer to 2013. Again the farm was already bottom 10 so it was still really bad. That didn't change and wasn't really expected to.
The outlook of the team changed with a craptastic 2nd half of the year. It was so bad that it got the GM fired and the team went into total rebuilding mode. I think that is a little over dramatic. Even with the horrible farm and pending departures of Upton and Heyward. I don't think the offseason plays out as it did if the team was good in 2013. I think they go for it again. And I think that would of been the correct choice. Either way I'm sure Kimbrel and Freeman aren't happy to have signed away their prime years on a rebuilding effort after having it sold to them that this core would stay togethor and try to win.