He's a leading thinker obsessively interested in this idea that everything around us is the product of a simple, fundamental ruleset.
He's sitting on the bleeding edge of human knowledge where, honestly, everyone is at risk of being full of shit. Scientific consensus isn't really any kind of indicator of future breakthroughs.
To each their own - let Wolfram be Wolfram.
I think his "new kind of science" needs to be singled out from Wolfram alpha and Mathematica as especially crank-ish. It appears to be an attempt at a grand foundational philosophical statement, but it doesn't interact with pre-existing literature that covers similar territory, conveys ideas with pictures and informal statements without robust definitions, doesn't have an underlying bedrock of concepts or uniform vocabulary, and doesn't have the focus or clarity of purpose to rise to the level of being right or wrong. And it nevertheless maintains a grandiose tone of establishing an entirely new domain of science
It's not necessarily wrong, but it is unfortunately very vague and concerningly childish, even though I think it does have some meaningful things to say. It's a very fair example in favor of crankery.
Cranks can do good work, but when they get out of their depth and don't realize it, blaming everyone else, that's when they become cranks.
I like Wolfram, and I think there are some interesting and fundamental insights in among the relentless self promotion, but ANKOS is a painful read, even though I find cellular automata a fascinating model.