[DTV]

It's not a news bulletin, it's a current affairs programme. The ident announcer pretty much sums up the scope of the programme:
"Now on BBC World News, hard hitting interviews and documentaries from around the world - Newsnight with stories making the news this week!"
(Yes it says "from around the world" but anyone who watched the WN repeats would know it's mostly UK stories..."

From what I recall, the specially edited global edition of Newsnight used to be more world-focussed - back when Newsnight regularly did 'films' from around the world. Of course, these have gradually disappeared due to Newsnight's budget being slashed, which meant more domestic political stories had to fill the gaps. From an editorial persepctive, network bulletins are also more UK-focussed now than they used to be and their (justified) presumption of familiarity with UK terms/news would make them unduly alienating to an international audience

Neither does World News AMERICA feel like a show targeting audiences around the world. It screams Made-for-America.

I don't think anybody has ever made any secret of the fact that BBC World News America is a world news bulletin made primarily for American audiences. Although it does include a fair bit of US news, it's still primarily a world news bulletin that is more suitable for international audiences than network bulletins. As ALV points out, a small editorial lean towards one region (typically those that are in breakfast or evening prime) is true of pretty much all branded programmes, and to a lesser extent of standard news bulletins. Plus, WNA is on during the 'night' for most of World's key markets, so, even if it was itself alienating, alternative programming is less of an issue.

While network bulletins are rebroadcast elsewhere in the world, nowhere are they big raters and services like SBS and NHK BS are non-commercial and specialist - unlike BBC World News. It might seem like a simple idea, but there are too many commercial, editorial and logistical issues involved for it to be workable. Even small things, like clips of sporting events, would have to be done completely different if network bulletins were being broadcast on BBC World News.