I know this would result in the loss of several days postings, but as the forum update seems to have been a complete disaster as far as I can see.
It seems logical,take the new site offline. Backup the database and files.
Restore the old database and files from last week, and put it back online
The setup a staging serve, for the new forum, restore the new forum DB and files to the staging server, and let people use it purely to get it working.
In a month or two when the new site is working, an update could be performed on the main site.
As a professional developer I have done updates on major commercial sites, and the new site is always trialled extensively on a staging server before its ever made live.
I have a lot of sympathy with your post (and agree with your analysis) but I doubt if it will happen.
I have been hoping (since the previous upgrade, probably) that we can get a commitment from the person who controls these decisions to participate regularly (like 3 or 4 days per week) in this section of the Forum.
Somebody with the ID of @mastrolinux made a very positive intervention in this Thread but, like @mrdanny (in the same Thread) he did not respond to my request to participate.
In my opinion we (as Forum contributors) need to get those people to come down from their ivory tower and mix with us peasants if any progress is to be made.
I agree that the input from a lot of dedicated people, to this forum, seems like its not valued by the upper echelons of the Arduino establishment.
If it wasn't for people like yourself (and a lot of other knowledgeable people), who give up a lot of their time, this forum would not have the following that it does.