so here is my proposal:
add top and bottom in/out to ALL nodes.
--if the node has a left side in, then it should have a top side in as well.
--if the node has a right side out, then it should have a bottom side out as well.
--you can use either, or both.
the bottom out would not work on nodes that already have multiple outs, ie: the switch node with more than two options. those would be the exceptions.
imagine the branching possibilities and better flow layout that could be done.