I often wish HN would just allow titles to get 
    posted and HN folks just have a discussion around 
    that. (Similar to Ask HN, but not necessarily in the 
    form of a question.)

Sounds like a real recipe for hivemind to me. I mean, any community struggles with hivemind a bit. But, at least with discussions centered around articles that exist outside HN, we get a little fresh air.

    especially if I don’t even know whether 
    this person is an expert on said topic.

He's a pretty respected voice, or at least popular on HN.

I find it very valuable to look into the authors of linked articles, see which authors pop up on HN frequently, etc.

Gives you an idea of who the leading voices in the industry are, helps you to know which way the winds are blowing.

Especially for somebody with a slower reading speed this may be crucial; helps to understand which article may actually be worth the time investment.