I realize that's a bit of a cop-out answer, but I also believe it's the correct one. It really isn't that difficult to figure out whether your product is exploitive.
What goals are you optimizing for? If the answer is: "I want people to spend as much time looking at my product as possible," that's going to lead you to bad places. If, however, you explicitly want to help people do X as efficiently as possible, as be done with it, you're probably on the right track.
If you're making an entertainment product, the calculous is a bit different, but still similar. Are you telling a compelling story that will teach us something about the world, or exercise our minds in new ways?
It absolutely is subjective. Two people may reasonably come to different conclusions on whether a given product is exploitive, particularly along the edges. Such is life. That doesn't make the analysis useless.
Dopamine is fine, it just isn't enough by itself. Playing a slot machine for days on end feels crappy in hindsight, even for the addicts who can't stop themselves from continuing to play. I'm concerned about how much of modern life is effectively becoming a normalized slot machine.
If you want to call experiencing stories, learning new skills, and forging new connections "long term dopamine", fine, maybe that's what it is. However, it doesn't take advantage of this very specific slot machine bug in our minds in order to become compulsive.
"I'll know it when I see it."
I realize that's a bit of a cop-out answer, but I also believe it's the correct one. It really isn't that difficult to figure out whether your product is exploitive.
What goals are you optimizing for? If the answer is: "I want people to spend as much time looking at my product as possible," that's going to lead you to bad places. If, however, you explicitly want to help people do X as efficiently as possible, as be done with it, you're probably on the right track.
If you're making an entertainment product, the calculous is a bit different, but still similar. Are you telling a compelling story that will teach us something about the world, or exercise our minds in new ways?