Things are progressing quicker than I thought. I have the display working for the planets list, but not the user interface yet. First, screenshot, then I'll explain how things will work:
Top left is the galaxy minimap. Top right is the list of planets that you have selected. If you select one of the planets, it will have the selection drawn on the star on the minimap.
The plan is to have a list of different planet filters below the galaxy minimap, and sliders that control the 5 different outputs below the planets list. Then there will be a overall output report below the sliders to show you the summary of your empire.
The list of filters would include:
Unoccupied planets (this would disable the sliders if selected)
Foreign-occupied planets (this would disable the sliders if selected)
Normal (no bonuses for construction)
Exciting planets (bonuses to research and commerce)
Mediocre planets (no bonuses for research/commerce)
Dull planets (negatives to research and commerce)
Fertile planets (bonuses to environment/pop growth)
Regular planets (no bonuses for environment/pop growth)
Infertile planets (negatives to environment/pop growth)
You can mix and match filters to select, for example, planets that are rich, but has negatives in other fields, and focus them on production. Or planets that have more than one bonus, you can select those specific planets and balance the outputs so it uses both (or all three) bonuses.
The sliders will be a bit different from per-planet sliders. Since different planets have different levels of output required for environment and agriculture, the sliders will be "relative" sliders. If you set one slider to 100%, and another to 50%, and the rest at 0%, it means the planet's first slider will be set at 66%, and the second slider will be set at 33%.
You can lock sliders, which will mean that those sliders are locked on all selected planets. It will be common to have the agriculture and environment locked since they automatically are set to clean/sufficient food per turn. So you can set 100% in one field without worrying about causing pollution and such. But if you really need to research something, or build something, or get out of debt, you can unlock the two sliders and slide the desired field all the way.
Let's say for example, a planet has 25% into environment, 25% into food, and both is locked. If you set all three remaining sliders to 100%, it means that the remaining sliders will have the remaining output percentage split evenly between them (50% / 3 = 16.6666% per field). If two are 100% and one is 50%, then the first two will have (20% and the remaining field will have 10%)
This will be a very powerful tool in managing your empire. I think it's possible that you will manage planets more from this screen than from per-planet in galaxy screen.
Getting excited yet about the macromanagement aspects of this game? :)