I will chime in and offer that there are has been a great deal of evolution of UI for layer management over the years. I really do not see the need to go in a different direction and in fact would prefer that the methods others have refined over the years are carefully considered to be used here. Not doing so leads to user frustration when things do not work as expected. A huge problem with Kicad in its present form is lack of adherence to common UI standards. Even a simple copy and paste operation is difficult to do.
I highly recommend looking at the layer controls used in other applications such as Adobe Illustrator, Photoshop and/or Affinity Designer and Affinity Photo. These companies have invested significant time and effort to develop and refine the layer UI over many years to make them understandable and to improve workflow. I think these apps would be good roadmaps to consider to generate a fluid and comprehensible Kicad UI that is consistent with user expectations. Not only that but I think these layer managers may provide some inspiration for other things that could be managed with layers. Things like layer hierarchy, grouping layers, layer effects, etc.
Someone mentioned an "eyeball" to show a visible layer. That is a good idea and I think I recall Adobe apps use an eyeball. The checkbox is fine as well. I would recommend the user should have the ability to lock a layer and use a padlock to visualize that. I like the idea of being able to change the layer colour without having to go to a special preference pane or multiple clicks. The obvious solution discussed here is clicking the swatch would bring up a panel to change the colour.
Opacity would be another helpful option.
As for highlighting the active layer, i really do not see much of a problem with the existing arrow. Another possibility would be to highlight the entire line with say something like a blue background.
I have attached a copy of the Affinity Designer layer UI below and a shot of the Adobe CS5 Photoshop layer panel.