This also suggests they’ve changed the role possibly into being a journalistic role rather than pure news reading. Slightly surprised with Tina being on the team they’ve retained a dedicated sports presenter.
You've probably answered your own question there. If she's writing and preparing the news she won't have time to do the sport as well, especially if Zoes sports person did as much on air as Chris's did
The people who have been writing and preparing the news for Moira won't just disappear though and it would be completely pointless for her and the 6 music presenter to write separate bulletins when a very similar if not the same script can work for both. I'd also imagine the sports presenter will have less of a role than before as Zoe will want to change the feel of the show as new breakfast shows are never successful if they try and imitate what came before.
It probably just means someone across the road can actually focus on their proper job rather than having to write bulletins as well as check them. Outside of Breakfast, it's actually quite funny seeing the duty newsreader running between floors every 30 mins for each bulletin.
I think Tina is great appointment, and has been said already hardly a demotion - it's the UK's most popular radio programme. I presume she'll also continue her work on Beyond Today with Matthew Price and, just like Mishal, I'm sure she will pop up as stand-in on various bulletins.
One I do feel sorry for is Justine Green. She's been after that gig all the time that Big M was there...