And if the save compatibility problem was resolved long ago, there would be no need to rework old stories and just focus on adding new stories.
In the end it's not that easy, I'd say. Most of the reworks happened for several reasons. First, there's a lot of old content which was written before Cpt. Sploosh joined the team and it shows and second there was a lot of old and pretty bad art around which had to be replaced to reach the certain level and to bring it on the rig system, which was needed to keep the game playable on android. So even if saves would have worked, the reworks would have happened in one way or the other anyway.
Unless of you want to say that DC should have known and planned everything better. I mean, it's a fair point but one has to keep in mind that he started this whole thing to teach himself coding and created a bit of rushed art to have something to work with. Nobody knew during the first 9 to 12 months that it would actually be this successful and when he actually turned the whole thing around and actually focussed more on consistency and quality, the game was already in 14.0 or so.
For the most part, I am pointing out why it felt to people that he didn't do much work during those parts. When in reality there is so much work behind it. And people don't know about it since they don't re-read the story that they previously played before. Also, I am also pointing out that many of the problems people complain about are valid since it becomes a vicious cycle.
That's certainly true. Even Diane's story improved a lot and gained so many neat details, even though the update certanly wasn't the best.
On the upside the line is perfectly clear since 0.17.0. (and to a degree 0.15./0.16.) too, because since that update everything that's new is supposed to stay as it is, while everything before it has and had to be worked on in one way or the other.
PS: The work for the next update is done and it looks like they started testing recently, so the game should be out within a week or so.