An army of decent rals? :-D

You are right more or less. In pre-HF17 world, your node was doing exactly same job as Hive account@timcliff's node is doing now with except that his witness is scheduled for block production because of votes (how frequent depends on amount of votes), and your witness was scheduled as soon as you've successfully broadcasted your computed proof of work (how frequent depends on cpu speed).
Now there are no miners so you don't need
miner =
lines, also you should get rid of your
mining-threads =
line. And voila. You have a witness node that is able to generate blocks for Steem network.
Of course that's not enough. In practice you need votes, even to use your stake you would need to do that explicitly with vote_for_witness. Do not do that however before bringing your node back to life because I suppose you didn't upgraded after HF17.
Good luck :-)