The ability to change the default enabled channels when using an Element Graph inside Asset Texturing or Material Layering workflows.
Justification
Currently, when importing an Element Graph as a layer in either of those workflows, it automatically disables either the Height or the Normal channel, as it assumes that they come from the same source.
However, sometimes when using external PBR textures, they carry different information. The normal map carries small details, while the height map carries large displacement information. Disabling either of them by default means losing one type of detail.
While manually re-enabling the channel isn’t a major issue, I think it would be valuable to be able to specify which channels should be enabled by default in the Element Graph itself.
This would be especially valuable for users who aren’t as interested in creating custom materials from scratch, but want to use InstaMAT to texture their assets with pre-created textures, add some AO, curvature damage, and call it a day 
Implementation Details
The simplest way would probably be to add a toggle to each output node inside the Element Graph, allowing you to specify if that channel should always be enabled/disabled, or just use the current default behavior.