I have few problems with this post, but I think I can summarize most of them to three.
For one, none of the aforementioned points is actually about breaking the "Show, don't tell" guideline; if anything they seem to be complaints about how "undercooked" some parts of the narrative are.
Second, the claim that the "child vs serpent" episode is the "proof that Kagha is evil" is a complete misfire on its own, because that's not at all what it is about.
Third, while there's no doubt that the current narrative has its fair share of "rough edges" that should be refined or marginally expanded before release, I'm starting to wonder if people realize that we aren't supposed to build home and spend the rest of our fictional life in Act 1, but that it's meant to be little more than a prologue -and an already fairly beefy one- and we'll soon move to the second act of the game, the area around Baldur's Gate, which is most likely where most of of the content will be placed.
And the whole "evil druids investigation" in particular seems to be intended as little more than a marginal footnote, not at a central plot point by any stretch.
I think what many - or at least some - people are afraid of is what you are talking about in your third point.
Now is EA, and people can test whatever content of the game is available so far. If they encounter a lot of things they don't like, of course the suspicion arises that the other acts will have similar problems.
Even more so when it comes down to mechanics that will stay the same, regardless of progress in the game, i.e. party movement and control, how scenes are triggered, how companions react to you, how in-game time progresses, how you fight your battles, how companions can partake in conversations, really how everything is presented.
