BBC News is a much larger organisation to bring into line. And BBC News has to manage their own budgets. It will happen, but in terms of time scale, its easier to handle the other channels and even BBC Weather as it moves to a new provider and new software.
That's just a lazy excuse IMO. Other media organisations (smaller than the BBC, but bigger than BBC News) have managed company wide rebrands on a single day and the BBC should have the confidence to do it too.
Unfortunately we are living in times where the BBC is seemingly on life support, and can not afford (in terms of money and press coverage) to be seen as "wasting money" on rebrands.
BBC News will no doubt see a re-brand in time, and it will have to work with at least the news bulletins, Regional, National, World and News channels. Global News may come at a later time or be included in the re-brand proper.
I could easily see the VizRT stations rebranding at once - wouldn’t that be BBC News, World News, The Nations (I’d assume), it appeared some of Global News runs Viz Opus (which can do graphics) so they could be included, and what London and Salford regionally? The problem would be those extremely outdated regions that are running systems that are what 10-15 or more years old and the one or two bureaus running CasperCG. They would all have to be recoded to match.
Don’t let anyone treat you like you’re a VO/SOT when you’re a PKG.