After trying the tutorials etc. I think that City Engine is a really great piece of software, but I still find the way you create rules etc. to be a bit scary for people like me who are not used to programming. I know that this is the reason why you also created a Grasshopper-like graphic interface, but it is still quite challenging. I was wondering if, for future versions, it would not be possible to add an additional user interface on top of the existing interface, to make common operations easier for users like me.
For instance, I could select some roads and click on an icon "street trees" to automatically add trees to these roads (I could remove/edit this attribute in the inspector, just as today). After all, the parameters for street trees are always the same: height, perhaps crown diameter, distance between trees and setback from the curb. I could also easily choose between different kinds of block types (I know that you have different block types in "Styles", I saw that in one of your videos, but I was not able to find these block types) and create buildings after editing them according to my specific requirements. Here again, unless you want to invent some very avant-garde blocks, most of urban blocks obey to a certain typology which boil down to perhaps 5-6 types, same thing for the buildings which compose them: rowhouses, sometimes with a back alley between two rows, semidetached houses, detached houses, courtyard buildings (like in Paris), U-shaped buildings, rectangular buildings, blocks with a big inner courtyard and spaces between each building... This way, we could already have default settings which we could edit by using the sliders in the inspector, while still being able to write some new rules for buildings and blocks which cannot be created by using predefined rules.
This is just some idea, but I think that something like that would be really helpful and would make City Engine even more popular!
We're constantly working on that user experience and are focused on making exactly those points you mention reality.
I cannot tell you yet in which direction it goes. But we're aware that by far most users don't like to code and that this could be avoided in different ways. So whether on the GUI or rules, we're trying to improve th user experience wherever possible.