"Let's get the light dome uplight reduction setting out of "edit the registry" mode and add controls to the light dome and HDRI setting dialogs that enable the user to turn reduction on and off.
Volumetric lighting
To be able to see beams of light shining through the environment; seeing sunbeams streaming through an open window, etc.
Caustics
Better simulation of true caustics passing through glass or reflecting from polished metals.
Fuzzy Objects
"AR creates its procedural clouds by inserting 3D ellipses and using fractals to "fuzz" their edges. Let's make this possible for any object in a model through Object Properties, so that things like smoke can be modeled and rendered.
Displacement Mapping
Add the ability to displace geometry based on imagery. Like a Super Bump. Useful for creating more realistic grass and brick.
UV Mapping
Similar ability to do UV Mapping as in Flamingo.
Heightfield
The ability to use a raster image to create a true 3D terrian.
Also use it like the displacement map on objects.
GI Fog
Better simulation of fog, mist and steam through global illumination.
Groundplane merge with sky, no haze
Setting in the Environment tab simply to merge the ground plane and the sky at the horizon, perhaps with a slider to control the blend, so that there isn't that hard distant edge to fret about.
Update Plant Editor
Fix know bugs
Plan and Elevation views of plant during editing.
Drag and drop elements (Branches, Leafs, flowers.)
Material orientation by face
The ability to map materials to individual faces of a solid.
Depth of Field
A realistic camera system that works as a photo camera. Realism increases very fast.
Date & Time stamping of Sun Study animations in Comotion
Assuming that Comotion as we know it ends up in AR5, it would be very helpful to have date and time stamping available as options for individual frames. Counting frames gets old fast.