I think Shelton is doing a fine job overall, but I don't think we really know anything about how he is "reshaping" this team. It's still incredibly early in his tenure and it's hard to draw much from a sample size this small. They are on pace to win 74 games, which is right where Vegas had them in the preseason. There are a ton of very talented teams underperforming now. The Twins are an undermanned team that is playing to their projections. Which is really all you can ask of a first-year manager.
And to be clear, if the wheels fall off, that wouldn't be Shelton's fault either.
I definitely agree you don't have to squint hard to see not just a competitive team, but a really good one potentially. It will take some players actually developing and a little more injury luck. But I think next year is the true start to a potential contention window in terms of the division.