Really interesting to read what you've written and I'd be inclined to agree with pretty much everything you've said. In particular
I want the dog to feel he's competing with the helper.
This is what inherently attracted me to Ringsports, everything I've read and been told about it is that at its base, Ring is supposed to be a confrontation between dog and decoy. Especially when you get to RingIII with object guarding where the handler isn't even present to guide the dog.
And from that, that's mostly how our club owner trained dogs. He never gave me a concrete example of a dog brought up exclusively on a defensive drive but the implication was very much that at this point it is no longer enjoyable
for the dog (I believe a dog can be serious in their task and still enjoy it).