Thanks for suggesting these updates! As mentioned in @justinf’s thread, we can definitely address the h1 issue – there’s just a blocker we need to address, mentioned here:
As for the meta language tags, you should see those on individual posts, which each have their own language value.
But we definitely need a default for the blog landing page, too. That was previously suggested in this feature request: Add default blog language. I’ve started working on this, but it’s a little tricky especially when people write in multiple languages on the same blog. I can take another look at that soon.