I like to think of Walt as INTJ in large part because of his vexed relationship to routine. He insists on it, yet for him it is joyless. He suffers long and hard to maintain the routine and persists with a claim that in this routine there is value. But it gives him zero joy. The value lies in some distant illusion then, some version of the family where good things happen, and his long-suffering approach to routine is his way of removing the temptation to intuit. Or at least, that's how he began the series, an ISTJ clone by choice.
Since then, he's spent quite a lot of time avoiding knowing the future too, to the extent that his MASTERMIND status is and should be doubted. Where are the reinventions of current circumstances? Where is the reconfiguring of all items so that a new path becomes visible? Where's the divorce and the escape to distant shores?
Either Walt holds an invisible key in his mind that he knows is there but can't display yet or he insists on routine because there is no other way forward. Both approaches might look the same. I watch the show imagining Walt's approach is the first and that this is Ni. And it should be that this will bring all sorts of horrible things into the world.
I still think Gus is INFJ too.
It's interesting. If Walt fails to triumph, and all this horrible stuff remains just horrible stuff, then Walt's a bad man. How confusing.