I'm not saying I'd call this project a failure at all, in many ways it's absolutely a miracle, but wow those have got to be the most depressingly rock bottom standards I've ever seen. This is what western game development standards do to a man
Thing is the changes could be minor, and have an enormous impact. There's a huge library of animations built up, just attaching any gameplay element to them at all could massively elevate the product. Then imagine what could be if they went the full mile and added say a social sim element where npcs could dynamically interact with each other and react to the player's actions, have personalities, opinions of each other, etc.
A lot of work? Absolutely. But it's nothing compared to skyrim style quests and third person action combat. Clearly the devs care about gameplay, or they wouldn't keep mentioning it for years. You yourself limited your praise to the sandbox, so perhaps you also feel it. Different teams or no, it won't be enough because the gameplay directions they have chosen are the most labor intensive ones out there. The ratio of dev time to play time is terrible. Player driven elements like the scene tools can remedy that, and interactive elements would only enhance them further.
The question the devs should be asking is how they can use the work they've already done most efficiently. One programmer could bang out a simple interaction system in 6 months using only assets already in the game, all without eating into the animation team's time, and I think it would completely revitalize the doubters like myself. Whose to say they couldn't add quests and combat too that down the line and make it even better? It doesn't have to be anything like what I talked about, just anything to incorporate gameplay into what they already have going.