I imagine the chromas she's getting will be the only two she's getting, and I can kind of understand why - as well as why people'd be frustrated about it.
So, for why it makes sense for them to do it like this (Gold+ in one queue for the skin, then a bonus Chroma for each other queue you reach Gold+ in) is that, for one, giving Chromas for unique queues was pretty experimental (as was a number of things - like Bonus Honor Rewards and tying Ranked rewards to Honor.), so it makes some sense that they'd try to ideate on it further than just "Get a Chroma per queue".
I think that the reason they chose to test this route was to make it feel more like getting the Chromas was an actual reward for effort to prove yourself in all of the available queues, over just pick-and-choosing which queues you want the color for.
And, I can also understand why people would get frustrated over it. Hell, even I'm kinda frustrated over it. When they added Chromas to the Ranked rewards for 2017, they set a pretty noteworthy precedent, and changing the formula (however unrefined it may have been) breaks that precedent, and doubtless makes some people feel worse about their Ranked climb.
I can also probably see it as being pretty irritating to Orianna mains in particular, since their main got shafted one Chroma while Graves mains can tout three to their Champion.
I think it may be a little too late to get a third Chroma for Victorious Orianna, but, this is definitely the time where feedback is gonna ring out the loudest, so if people want Chromas per individual queue, this'd be the time they'd tell it.