Threads with rl names could have those posts deleted but the threads still stand. Might encourage better posting behaviour.
I agree with the OP and I am pissed off to see how easy it is now for a poster to cry 'But this will identify me! Waah! I'm SOOO upset, I have ANXIETY don't you know' on threads that haven't gone their way and were not even particularly identifying anyway. 

After hackergate MN said anyone who wanted their entire history deleted could have it. I thought about it, but I saw so many great threads decimated overnight, no longer making any sense due to the amount of deletions, which was such a shame and I actually felt a bit sorry for MN. I felt the archive was important, the history and the community's backstory was important, evidence of all the support and the great laughs we'd shared were important.
What I did do was make a conscious decision to post in a much more circumspect way and I started to NC frequently, along with most other people.
I have quite an identifying backstory that I talked about a great deal at one point under my old regular name. A while ago it came to my attention that a family member I have moaned about a lot on here is probably here too now, and I REALLY don't want them to find me. I found as many very identifying posts as I could and reported them for individual deletion. I apologised to MNHQ for the piecemeal nature of the deletions and said that if it was easier they could just delete all of my posts from certain threads rather than just the identifying posts, but I they said they really don't like to do that because it makes the threads look like Swiss cheese (their words.)
However, several months ago I came across another couple of posts that really identified me (names of my children and name/breed of my pet) so I emailed MNHQ asking them to remove those two posts. And for some reason they won't do it. 
Admittedly I am locked out of the email address I use only for MN so if they had contacted me with a reason then I can't know what that reason is, but I have asked them twice now and those posts still stand. 
I realise it was my own fault and I should have been more careful. But to be fair MN was a different place five or six years ago compared to now. Most people had never even heard of MN, now there is barely a day it's not mentioned somewhere in the media. It does piss me right off to see whole thread deletions happening almost daily on trumped up grounds of 'privacy' and yet I can't get this one small thing. 
I wish I'd deleted my whole previous history while I had the chance.