reset_node_keep_connections.py

import bpy
import itertools


def store_replace(node):
    node_tree = node.id_data
    props_to_copy = 'bl_idname name location height width'.split(' ')

    reconnections = []
    mappings = itertools.chain.from_iterable([node.inputs, node.outputs])
    for i in (i for i in mappings if i.is_linked):
        for L in i.links:
            reconnections.append([L.from_socket.path_from_id(), L.to_socket.path_from_id()])

    props = {j: getattr(node, j) for j in props_to_copy}

    new_node = node_tree.nodes.new(props['bl_idname'])
    props_to_copy.pop(0)

    for prop in props_to_copy:
        setattr(new_node, prop, props[prop])

    nodes = node_tree.nodes
    nodes.remove(node)
    new_node.name = props['name']

    for str_from, str_to in reconnections:
        node_tree.links.new(eval(str_from), eval(str_to))


def main(operator, context):
    space = context.space_data
    node_active = context.active_node
    node_selected = context.selected_nodes

    # now we have the context, perform a simple operation
    if not (len(node_selected) == 1):
        operator.report({'ERROR'}, "1 nodes must be selected")
        return

    store_replace(node_active)


class NodeResetOperator(bpy.types.Operator):
    """Tooltip"""
    bl_idname = "node.delete_and_rebuild"
    bl_label = "Reset Node (keep connections)"

    @classmethod
    def poll(cls, context):
        space = context.space_data
        return space.type == 'NODE_EDITOR'

    def execute(self, context):
        main(self, context)
        return {'FINISHED'}


def register():
    bpy.utils.register_class(NodeResetOperator)


def unregister():
    bpy.utils.unregister_class(NodeResetOperator)


if __name__ == "__main__":
    register()

@p2or please see the current state: https://gist.github.com/zeffii/010a108a612fd6071a4b