For example, most of the distribution options (altitude, slope, distribution maps, etc...) could be removed, and instead distribution could be simply driven by set of maps. Therefore users who dont need anything complex will not have to put up with a spaceship command panel ( http://i.imgur.com/m03zpsd.jpg ) and those who need flexibility can always do it.
Altitude and Slope are Extremely useful for me. I use them all the time with great satisfaction. I would never think of removing these.
You could simply support falloff map for example. Distance blend in world Z axis with some output curve clamp could easily work to define altitude range, but with even more flexibility, such defining how smooth the gradient is, and curve of it. Perpendicular/parallel mode in world Z axis could work to define slope range. Various procedurals could be used to drive distribution. Fractal noise stretched in one axis could be even more flexible equivalent of for example random bands distribution maps, and so on. Some sort of distance texture could work as a include/exclude area for meshes.
Adding additional ways to drive distribution/faloff is a great idea. But you must realize there 1) there is already a map distribution option and 2) the current altitude/slope are tied directly to the geometry--which isn't always controlled by an easy-to-manage mapping. Complex geometry (that includes cave systems, etc, as an example) would probably require extra work because of needing to unwrap, etc, objects that don't currently require unwrapping because we already have geometry that is mapping actual geometric coordinates to real space rather than texture space.
As it stands, having the ability to distribute via Map + Geometry offers great flexibility. Unless your entire geometry is already driven by maps (which is only sometimes
the case) then the map+geo option is best.
Most of the people do not use billboards..
This is only an assumption. Have you polled most people?
And Render frame in Display rollout is completely redundant, and just adds more space for error.
Do you mean the Render Group UI? That is a terrible idea to remove those options. It is standard for many Max components to give the user control over viewport/render settings. While a final render is likely to have all settings all the way up, different iterations of renders can have usefulness for different phases of projects. So when you are building the composition, you might do some fast renders
with proxies and later change to full mesh.
I just feel like these recommendations are mainly overly critical of Forest in non-essential ways or in very specialized ways.
I am a firm believer that almost all things can be improved, including Forest. I just don't see these recommendations as truly sincere. The number of rollouts in Forest is really unimportant. If you don't use the Material rollout, don't open it.