Hello, backer of the game here, I'm basically the only person who has uploaded screenshots of the game onto the store page lol.
let me see if i can answer some of your questions.

Okay, so basically in a way yes. The original heads, the ones who launched the kickstarter handed the reins over to a new team because, to quote the new lead from the AMA they did a while back

"The team signed with Freedom as publisher, the game was gearing up to be a success so more budget was available. With that extra budget, they decided to add more of what they would consider "cool stuff" which meant adding a multiplayer mode, and switching to a brand new 3D art direction. The issue is that they didn't foresee all the implications of such changes and the project started to struggle.
At some point, the team pretty much lost their way and therefore their motivation, and they were burnt out. Without a change of staff the game would not have released most likely."

So basically, The old team got the extra funding and instead of wanting to polish what they had made up to that point, they wanted to add all these bells and whistles to the point where all of their "fun ideas" became too much for them to the point of the game almost being cancelled until the new team picked up the pieces.

This isn't to say that no one from the original team is involved, a good number of the original team are still working on the game.

As for why after the change they couldn't revert to the original art style that they had going before....I dont know. it could very well be because the original devs scrapped the older source code, or that too much money has already put into the change to 3D that they could not justify scraping everything they did again up to that point.

They are still putting in mini games into the new game. With my tier, I have hands on experience with the latest alpha builds that are given to us, which with this build included their fishing minigame. Which, not going to lie, is actually a lot of fun. They also have a machine repairing minigame thats also alright.

And with hands on experience with the game, the art style really doesn't clash all that much for me. But I can completely understand not liking the change, as if a game looks "good" really does depend person to person.

From speaking directly to the new lead, partially from their monthly AMAs and from our personal kickstarter group chat, they said about 90% of what was going to originally be in the game will still be in the game, with mostly a few customization options no longer being able to make the cut because of the drastic change of art style. But things like splicing your crops, will be in the game, just maybe not in early access.

I actually ended up asking the new lead dev about why they didn't go back to the sprite based graphics when the change happened.

He told me that by the time they get their hands on the project, the code for the engine itself was about 90% done. They did even ask if it would have been possible to revert back to how it was before, but it would have meant scrapping everything again and starting everything over again so they decided to keep with the 3D and work on refining it. Otherwise there would have been a good chance that their programmers may have bailed on the project because needing to start everything over a 3rd time.

With that extra budget, they decided to add more of what they would consider "cool stuff"

The main reason its a technical one, being able to save at any point would require a more robust save state for any feature we have. I belive in the theory you said, give player fhe option and let them play how they want. Once the save system is robust enough to handle any time saving it will become a thing :) but its not there yet