Something i wish to see in the future versions of kicad is highlighting a trace when a mouse hovers over it. Not like when control click where the background is grayed out. Maybe grayout 30% or even less of the background such that the trace is highlighted. This same could be added to the eschema as well.
Another would be grouping of components in the PCBnew. Sometimes i need to populate only couple of components on the PCB so i could create a group for those and possibly export only the active ones so that those do not have to be manually written down. This would be better if this option is available in the Eschema itself.