And yes, the distinction is pretty subtile and the perception of witnesses true role is complex as you stated.
I think the consensus is more about the perception of who is honest or not than about the witnesses. Witnesses units are just milestones (and assistants to validate previous transactions as fast as possible) in the path until the genesis unit which allows normal nodes to selected the best/main chain.
But, imo, you can't say "they are just milestones" when they are a key element. The referee of the match. The flow that makes transactions confirm and root them into reality. The path that all users follow to achieve finality of data they post.
Can you have a formal match without referee? No.
They are THE milestones.
Also I wanted to share another thing.
"well, we dont need to focus on tps because low usage...". But I see it differently:
Can be presented byteball to, for example, google, and ask them to be a witness, with a transaction platform which "only" achieves 15tps and clogs up at 20? NO.Can be a good advertising the real tps amount after improvements? YES YES definitely yes.