I haven't actually noticed a reduction in shitposting,as far as I know things have remained fairly the same way at least for a while now, except probably cos you've been away for a while
The bitcoin discussions board is still in its worse state,likewise the AD, while meta is still mostly filled with ban appeals which means people are still doing the wrong things by stealing others works.

I think the last time we actually saw a visible change was few days/weeks into the new merit enhancement for newbies,the quality of posts increased a lot during that period,but it all seems to have died down slowly