It looks like there is currently support for Linear Gradients. But I see no RadialGradient type.
I am assuming this is in the plans.
Also I think it would be absolutely freaking awesome if you had Polar Gradients. I always wish Flash had polar gradients and you had to do some really stupid workarounds to get them to work.
Also useful, Perlin Gradients or Bitmap Mapped Gradients…
I totally agree on the wish for both radial and polar gradients. I’ll make a suggestion to the Fuse libs team to see what they can come up with. 
No immediate promises though.
Path based gradients would be great for strokes.
OOOH… I totally forgot about Diffusion Curves! Holy crap… if you could make Diffusion Curves a normal thing inside Fuse. I would quit my job and become an evangelist.
In the hands of a real artist, Diffusion Curves could be a huge new way of drawing. It far outpaces Gradient Meshes in Illustrator.
If you wanted to, you could build a lower fidelity Diffusion Curve… Maybe an Alternative to a Linear Gradients could be a Quadratic or even Cubic Gradient where you get one or two extra control points to “bend” the gradient. You could get some pretty complex gradients by layering these effects that way. It would actually negate the other types of Gradients I mentioned.
I created an interactive mock up to demonstrate how Cubic or Spline Gradients could work… https://dl.dropboxusercontent.com/u/1256960/%20Research/AS3/DiffusionCurve/CubicDiffusionCurve.html
There would need to be some research on how intersections and kinks would be handled. Also the color should “pad” or extend to the outer regions of the shape.
