Regardless of acquisition, they tend to put cards in content that requires continuous play; or rather, encourages it.

I didn't consider Alchemists, and yes that would make sense.

Let's say that gathering was an added factor, I can't imagine there to be very many of them as they would need to be tied to a nodes spawn family (4-6 nodes that you alternate with for gathering). But I'm not sure how best you would make it spawn. I guess you can make it random chance like maps in hopes that it spawns. Or if tied to unspoiled nodes a random empty slot.

I suppose the second thing to note would be what the face of the card would picture and the quote/lore associated to the card description. The most obvious that I can think of, if we were to go with gatherers would to have a card per area/region and have the face image be something in regards to the land or landmark in the area. That would nicely cover miner/botanist. For Fisher I suppose in that line of thought they could be a desynth reward from fish where the fish is the subject in the card (wether it be common or legendary in nature)

There wouldn't be much challenge in getting these cards though and if there wasn't a limit to acquiring them, than you can farm them to sell for mgp. Also, if you were to diminish the current sale price for cards as is, that might also deincentivise players, so I'm not sure how you would combat that either.

I could play along with the idea of gathering acquisition for cards but only if it can be done in a way that makes sense in the game. I know a lot of changes players want in ARR zones are challenging for the devs because it's already chalk full of event flags and adding more can interupt those flags, so it's hard to say.

Like I said, I do want more for Triad but I'm not sure if there's enough here to make it work