I am joining this discussion, as there is more development towards node based workflows (geometry nodes, particle nodes, animation nodes) and also multiple addons which use node graphs.
Change towards vertical design is necessary, as in large node trees horizontal layout creates much longer setup than vertical and is less easy to work with. In example, if there is a small setup of 10 nodes arranged horizontally that makes it quite long already. But if 10 nodes are arranged vertically, those will take less space. To think the same with 50 or 100 nodes, then it makes big difference to work with.
Above Nuke screenshot is a good example of this, as it has nodes both ways which is needed in real situations. To get this benefit the design should also follow Nuke with nodes being just used to access their properties which are in separate panel and not to have properties inside nodes, which can make nodes very large if have many options. Small nodes without parameters allow larger overall view while working, as no need to zoom close to individual nodes to change parameters. Nodes itself don’t need to display inputs all time, but only when hovering cursor on top of node. Nodes could display possible output/input connections as a pop up on mouse hover.
This should be the standard way, but it is not limiting to vertical graphs, as users can also create horizontal if prefer. I am actually thinking that it could be possible to have current way and proposed way coexist by having a node editor option to choose either “compact” or “old” node graphs. Just to change which visual style to use. Compact to be described Nuke style and old just like Blender has now, so nodes are bigger and also display parameters and inputs.
Also everyone who has used Nuke knows that its node graph superiority is largely because of how convenient it is to work with. Everything is really easy to select and connect. Blender and some other software have very small selectable areas and connection dots. Blender works quite well even zoomed out, but output/input dots could “pop out” more clear when hovering mouse on top. Also framing nodes and reroute dots works much better in Nuke. To move nodes out of frame in Blender, user needs to use a shortcut to disconnect node from frame. In Nuke user can just move nodes out or inside frame. Also reroute dots in Blender are fixed in place, while in Nuke dots can be just dragged to new place as those are directly moveable. Dots have also much larger selectable area in Nuke. Nuke also does good job of aligning nodes automatically when close enough horizontally or vertically to other nodes to create clean understandable setups. Nuke’s node graph might look more ugly but it is very user friendly.
Lot of comparison to Nuke, but it has the best node graph there is. Houdini uses 2 types of node graphs. Nuke style in general, but shaders are similar to Blender’s. So combination of 2 styles is also possible.