Although this is a very minor thing, I am finding the Surface Layer shader drop down menu used to select one of the following options, "Coverage, Breakup", "Altitude Constraints", "Slope Constraints", "Effects", is a step backwards for the GUI in V2.4 compared to simply having these on tabs as is the case in the V2.3 Free Edition. It means two mouse clicks to access the parameters instead of one and it is less clear what options are available. In addition the Distribution shader still uses Tabs for an almost identical set of options, so the new approach is inconsistent.
The same comment applies to Cloud and Atmosphere layers, the options were easier to access and more obvious when they were Tabs.
I would like to request that in the next release the drop down menus are changed to Tabs with abbreviations where necessary (colour - col, Functions - Fn...) Terragen has a very clean easy to use interface. This change would make it even more so.
One other minor GUI change that would be useful would be to be able to toggle a node's "enable checkbox" from its RMB Click context menu in the Network editor.