Adjust the hue/saturn/Brightness contrast of a gradient.
Well, I think a Hue/Saturation-Adjustment Layer clipping masked to the Gradient-Layer might be good enough as it is.
Interactive gradient lines like in illustrator.
That I would agree would be an improvement.
I’m not familiar with Inkscape, so I don’t know what features that would include (perspectival shortening?), but it might be more convenient that the work-around with Smart Objects.
How do you propose defining the ellipse for elliptical gradients?
I imagine it as there would be two ways to create the eliptical gradient.
One for layer FX and one for the gradient tool.
The layer FX, could work as the circular/eliptical gradient in inkscape. With control handels for direction/center and width. With the addition of repeats.
The gradient tool could work as a twostep rocket. Many 3d programs work this way when you create a new object.
1. First you drag the direction and length from the center. (Or hold alt to drag from the corner?)
2. When you release the button the mouse will adjust the width. When you press the button the second time it will apply the gradient.
"Well, I think a Hue/Saturation-Adjustment Layer clipping masked to the Gradient-Layer might be good enough as it is."
It doesn't work in every case and its also requires you to allways copy and remake the layermask when applying the gradient to another object on another layer.
For example: When you apply a gradient FX inside a object together with other effects such as innerglow or a pattern. An adjustment layer would also change the color of all the other effects.