360 needs some work done on the STL out for 3D printing as well as simulation (though that's never a good way to go). A replication of what's in standard Inventor would be super useful - finer control over tessellation, some sensible presets, and a preview would make it about perfect.
Control over the output from assemblies would be good too.
Not an issue if you're outputting a single STL from an assembly, but some additional options and control when creating separate files for each part would be - in particular when there's multiple references to the same part.
Perhaps with a flag in the file name for multiples when working with separate files to indicate you need multiples and how many (think Bolt_5mm_count2.stl).
Al