okay, let's start-
1) a number of settings you want control over in your proposed "Galaxy Forge 4" are actually controlled in entity files. I'll use the # of resource roids as an example- this value is controlled in a planet's entity file.
2) the same goes for gravity well radius/diameter. Also controlled in entity files.
3) I fully support the Z-axis alteration idea. Excellent I must say.
4) an "in-engine" editor will probably not come; unless you intend something like a representation when zoomed out to the max in Sins (where you have the solar system spiral-things), in which case that might be doable, but might not be a good idea. A 3D-rotatable representation is a FAR better idea.
5) Planet textures are a function of the planet meshes. Each planet entity lists 2-3 meshes, each mesh has a different texture set.
6) we don't need beer in Galaxy Forge 4. And when you express it, do so like this: 
7) I didn't notice anything bad about your grammar/spelling. Well, very little anyway. But enough people who speak English and can't spell already inhabit large swaths of the Internet, so its pretty unnoticable.
That about sums it up. A tip though- if you want to edit GW (<-shortened term for "Gravity Well") sizes, simply convert the entities from BIN->TXT so they are readable in a text editor, then edit the file by hand in Notepad, WordPad, or Notepad++. NP++ I recommend. Same goes for editing resource 'roid values.