I don't think so. HN has been hell banning for some time, often quite unjustly, but the general quality hasn't been affected by it.

Are you sure? I can see a correlation between the rise of hell banning and the decline in general quality.

I recently started browsing with dead links active and have noticed a couple of seeming hellbans on people where it really didn't feel warranted to me based on the recent history around where they got hellbanned.

Of course, this forum isn't a public commons so the moderators can ban whoever they want, but there are some cases where it seems fairly arbitrary.

While it is often unjust, it is often extremely just also. Personally, I don't know if the tone has really changed. I do know that I see less demonstrations of work done on the front page. That's a shame :(