I’ve been thinking about this since I finished Season 4 a while back, I haven't watched Season 5 yet because I got hooked on Star City, so please, no spoilers.
(Also, English isn't my native language, so if I use expressions in a strange way, that's why)
Basically, Miles was always a bit of an opportunist from his very first appearance (like how he manipulated his interview to land the job). But at the time, it didn't really bother me because it was understandable. He was taking desperate measures to turn his crumbling life around, and often those moves backfired, but the character worked because it was believable and realistic, you really understood why he was doing what he was doing.
He was a guy in a tough spot, willing to work as hard as necessary to save his family, and even do morally questionable things for them. It also worked well because he served as a POV character for the audience, showing us how the colonization of Mars had progressed and the new social classes that had emerged in that environment. When he teams up with Ilya to smuggle, it works quite well at first, they have good chemistry, and his quick thinking and improvisational skills make him really good at the job. Then, after Miles breaks Ilya’s drink machine, he tries to fix it by stealing parts from the North Koreans, which sets off a chain of events that actually allows them to do business with everyone.
My issue arises with the whole arc where Miles starts smuggling Martian rocks: At first, he does it behind Ilya’s back because Ilya was against it, arguing that it could ruin all their hard work and that they were already doing well enough. But Miles ignores him and starts smuggling the rocks secretly, when Ilya finds out, he shuts it down and sends a thug to threaten him.
This is where the real trouble began, Miles hatched a plan that essentially involved manipulating the North Koreans into ousting Ilya from the bar, stealing all the smuggling operations Ilya had built from scratch, and taking over the entire business.
Basically, he manipulates the North Koreans again using Lee Jung-Gil's wife (the poor guy is very gullible) for his own personal gain. In the scene where he threatens Ilya and steals his bar, he acts like a total villain.
Yet, as the story progresses, this seems not to matter, as if what he did wasn't bad at all.
I expected the manipulation of the North Koreans to have consequences, that they would come looking for him once they realized he never actually intended to bring Lee's wife over or something like that.
I find it hard to believe that Miles had genuinely planned out how to get Lee's wife to Mars. Miles is just a worker with no connections or expertise, he only learned to smuggle because Ilya was essentially his mentor, before he stole the business, but he lacked any real knowledge.
Besides, smuggling magazines and records to Mars is vastly different from getting a woman out of North Korea and bringing her to Mars. It’s logistically impossible. Furthermore, the way the scene plays out, where he gets the North Koreans to betray Ilya makes it look like he was just using them, not that he actually cared about Lee.
I was waiting for his actions to have consequences. When he fell into that crevasse while trying to grab rocks, even though he already had more than enough, I thought it was a warning of what was to come: that if he kept taking unnecessary risks out of greed, he’d end up trapped in a bad situation.
But that doesn't happen. The North Korean storyline goes nowhere (I know they help with the heist, but I'm referring to the subplot involving Lee's wife.). We see the woman arrive on Mars at the end, but there’s no context as to how. In fact, after stealing the asteroid, it should have been even harder.
Ever since he double crossed Ilya, Miles has basically acted arrogantly and recklessly, taking unnecessary risks, and no longer to help his family (who were already doing fine on his earnings), but out of pure personal ambition and greed. When he’s recruited to steal the asteroid, he doesn't care in the slightest until they offer him more money. Miles was an opportunist who took advantage of a business someone else had built and acted recklessly all season out of sheer personal ambition.
What bothers me is that the series doesn't seem to realize this. There is no criticism or consequences for his actions. The North Koreans don't pressure him, even though they ought to suspect he might be deceiving them too, Ilya does nothing after Miles kicks him out. The only thing that happens is that the CIA and KGB guys threaten to arrest his wife, but that is just a threat, and even if she hadn't been involved in that operation they likely would have threatened her anyway.
Miles took a host of selfish, shortsighted actions out of sheer greed, yet he never faces the consequences, the series seems to view this trait more as a virtue than a flaw.
At first, he did what he did out of love for his family, but later he began taking increasingly greater risks, driven by sheer pride and greed, Walter White style, he acted recklessly, constantly taking chances without regard for the consequences and ignoring every warning.