I see where you're coming from. But let me tell you why I think you're just being frustrated and unreasonable.
Reworks, even partial ones, take time. A lot of time. Look at the roster updates: they're announced almost a year in advance, and the actual reworks are done almost half a year later. Most teams are in charge of one major rework and 1-2 'small' ones, so let's say the time is divided equally between the two (I'm pretty sure the big ones take more like 70% of the time budget).
Anyway, if it takes 5-6 months from announcement to release, then it's 2-3 months for a team to rework a champion at a medium scale.
Now, these one-off reworks don't even have a full team working on them so they could take like 3+ months. The whole thing is decided and starts being worked on WAY before you even hear about it.
So it's not like Aatrox's partial rework is "something that needs to be looked at but they keep ignoring it and doing Nida instead". There's probably an entire Design Resource Allocation Department that decides who works on what and for how long. If Aatrox is getting looked at, then 1 animator, 1 designer and 3 assistants will be dispatched for him. It's not like "some guy" is supposed to rework him but he keeps fiddling with Nida instead.
Rito has said (and their timeframe proves it) that they have multiple teams working at the same time, and also that the Balance team is totally different than the teams working on the Rework pods. So trust me, balancing Nidalee around is NOT slowing down work on Aatrox.
If they're working on him, they're working on him. And since they announced it, it's probably already under way- they tend to not announce things that might get cancelled because this community can't responsibly handle frustration so they'd rather not tell them at all than have to deal with an angry mob.
And tbh I don't think Nida has been getting so much attention anyway. Just a few balance passses over the course of several patches. And right now she's not even relevant, so I totally see why they want to give her a boost in the new jg. As I said, it doesn't even affect the reworks in any way.