Okay, let's get this one thing straight: This A minecraft story not THE minecraft story. Anyone who has ever played or seen a Telltale games game know that they only write spin-offs. Let's start off simple here.
Why is there no "Steve"? Simple. How many people do you know that do not have a skin? Not many, right? Steve (and the lesser known Alex) Do not exist. They are templates for you to craft your own character around.
Why is there no Enderdragon? Again, pretty simple. The dragon isn't even the "final boss" of Minecraft, so using it as a point of argument is useless. The next problem with your statement about the dragon is that you say that it needs to be defeated to "beat the game". I don't know for how long you've played Minecraft for, but anyone that was around since before 1.0 knows that you can't "beat" the game. Minecraft has no endgame, since it's a game about your actions and creations. A game like that cannot be beat. You could argue that getting all achievements could be considered as beating the game, but that's a different story.
Next up, the animation style. Yes it's true, the fans did that first. However, no matter what you may think, Telltale did not "steal" anything. They probably saw the animations and though "That looks pretty good, we should do it like that." This is perfectly legal and acceptable, even without attributing the original creator, due to it being an idea. The only way that it could possibly be illegal is if they had patented the animation style, which they quiet obviously did not.
The same as before goes for the whole Aether thing. It's simply an idea that they liked and wanted to use. Simple as that.
Now, gameplay. This is a telltale game. Telltale only makes adventure games, therefore it is reasonable to expect the game to be a adventure game. This game in particular is a much better fit then Tales form the Borderlands, which is based on the Borderlands series and anyone who has played those games know how very shallow it's story is. With Minecraft, however you have the advantage of a mostly blank slate. Minecraft has no story, so therefore they are not bound to much.
Anyway, enough of me being a keyboard warrior. Personally I'm not going to buy this game, at least not until the first episode comes out and it's solid adventure gold.
The only problem that I have with this game is that it's stops the studio from working on The Walking Dead Season 3