I wasn't comparing anything to S1 other than her personality, which stayed the same. Back during the S1 and early/pre-S2 threads there was a lot of "how do we know Jackie would go for Marco, we don't even know her personality," to which I'd argued they'd given some indication. Now maybe I got lucky and they developed the same traits I'd noticed, but from my perspective that indicates they'd never intended Jarco to NOT briefly happen, or more accurately they'd never intended to make Jackie look totally wrong for Marco.
My point, which I didn't directly state, was that the Jackie relationship happened to the minimum because it's never supposed to last beyond the brief relationship it is. Even in-universe, apparently Marco avoided her out of anxiety since Bon Bon.
And while showing that relationship minimally would be bad writing if we're supposed to really become invested in it or see it as deep, it's acceptable for something that we're supposed to be seeing for what it is-- they had 2 dates, which we saw, it's not awful but it's not going great and it probably won't last.
So in that sense it is being used, just not ideally for some. And I do think many are shippers being annoyed that the relationship isn't being given a "chance," when it can only develop according to the creators' plans anyway-- which from late S2 on were pretty clearly "it won't last."
Though I didn't say the character was written poorly, and I don't think anyone said that and it wasn't what I was responding to (could be argued that the relationship was written poorly, although the in-universe explanation provides an excuse-- though that could be seen as bad writing as well),
My point was the apparent surprise some people are expressing about Jackie not seeming to be prominent, when the writing was on the wall the entire second half of S2. People are annoyed they got "invested," when if she was written in a shit way so said investment wouldn't happen, that'd make the writing worse.