I don't see it so much about good vs bad, because few things can be categorized that easily. I think the issues around AI involve trying to assess how it will change our lives ( I think those changes will be massive) and how to adjust accordingly.
Now coming to "critical thinking." Why do we want people to think critically? Why do we want our kids and students to think critically? Is "critical thinking" an end by itself or are we trying to achieve certain personal or societal benefits through critical thinking? If the end is some other things and "critical thinking" is merely a means to achieve that end, what if AI can get us to the end faster?
In my opinion speed is not necessarily better. And it shouldn't be the only consideration. Focusing only on efficiency ignores a whole host of other possible issues that I think we can ill afford to do. The potential societal impacts are huge.
Can we get things done faster and possibly more cheaply with minimal or no human intervention? Sure, but that leaves a very large segment of our population without jobs, with a resulting loss of income and also personal satisfaction that seems to be a basic human need for many. Even if people were "taken care of", I'm thinking a lot of them will still have a fundamental drive that will remain
As far as "critical thinking" is concerned, maybe future humans will evolve in a way that they no longer have the need for control over their lives and a need for free will, but I'm not at all certain that is likely. I personally wouldn't want to live in a society where someone else wields all the power and money and who makes all the decisions and I'm just taken care of like a pet. Or the alternative scenario, that I have no way to make a living and have to struggle to survive.
They will be interesting times no matter how things play out.