When a user replies to a post, the default is ‘tracking’. Is it possible to set this default to ‘watching’?
There is a Preference for this.
You should use user preference site setting
default other notification level when replying to change it for all new users.
Is there a way to change the default preference for existing users, similar to what you can do with How do I set category tracking level defaults historically ?
Ideally this process would change the default for those users who haven’t touched their default, and respect the option for users who have changed their preference.
Yes, the site setting offers to make this change for you now when you change it. This is a very new feature in latest.