I'd imagine to once it is settled in Salford the BBC would want to return to at least a Mon-Thu lead presenting team - it's amazing really how many TV folk get away with a 3-4 day working week when most the top radio DJs front shows five days a week.
My dad works four days a week and he's not "getting away with it", he does it because he works long and inconvenient hours. And he doesn't work on telly either, he works in a factory. And my mum works three days a week and isn't "getting away with it", she's doing it based on the schedules in work and the work-life balance she wishes to maintain, and is paid accordingly.
And I'm pretty sure presenting three and a quarter hours of complicated live television, getting up at 4am and having people on the internet slag you off every day is quite hard work, actually. You may as well argue Brucie should do The One Show as well as Strictly because at the moment he's only got a one day working week.
In addition, it clearly makes sense on a programme where you have a presenting team to vary the line-ups and not highlight obvious senior presenters that are on every day, because that means the appeal of the show is too wrapped up in the presenters and if they leave then there's a huge chasm and the ratings could plummet. Whereas if you have a team of four regular presenters the show is the star and not the presenters.