It absolutely could have been (and was actually originally planned to be) at least one episode longer. However, by the time the game was reaching the final few episodes, and the dev had already invested years into the project, he was actually pretty keen to get this finished and move on to another project with what he felt he'd learned from feedback. An entire episode was cancelled at the 'last minute' and the final episode and epilogue were changed from the original plan. I left the project at this time, and receive no royalties or payments for the finished project, and have no regrets at that decision. If the final showdown feels a little rushed and anti-climactic, well, that's because it is rushed and anti-climactic. The previous plan had the final showdown be far more epic and many reviews and feedback have stated the ending that appeared felt at least a little rushed or lacking. That said, the dev put a lot into the epilogue, and I think that in such respect, the overall finished product is satisfying.
In addition to the ending, throughout the story one frequent complaint or criticism was that the story at times leapt very suddenly from one scene to another. This too was a decision made to compress the overall story into a manageable amount of episodes and seasons. There was an awful lot of story crammed into the original plan, and telling it all was always a pretty big challenge. It would have been very easy to make the transitions less jarring by expanding and extending what was created, but it was felt it was a better overall decision to move the whole story along, and not further extend the amount of time it would take to reach an eventual conclusion. (Which is why I myself left when, at the last minute, all such previous decisions and commitments to the story and scope were cancelled to change the plan and simply finish it faster).