I‘m really not seeing this crisis tbh, maybe I don’t visit enough but pointless salt threads are fairly rare and are usually locked pretty sharpish.
I see a fair amount of posts I feel are moronic but I’m not sure what can be done about that save heavy moderation and policing. HearthPwn is a well recognised forum for a game which attracts a younger audience and this is generally the result of that. I don’t know any large mainstream gaming forum where this doesn’t happen.
There are other HS communities out there which probably offer more of what you are after. Like I said CompetitiveHS fits the bill, I’m pretty sure nerf threads are against the rules.
Duplicate threads (like Tick threads) and threads with no content other than salt being deleted seems fair (and from what I’ve seen the mods do a good job of this), but deleting threads because they are critical of the game seems a bit silly.
If you want to discuss strategies then r/CompetitiveHS is probably a better option.