Not necessarily in our country The Voice has two presenters and they even have a third presenter doing the backstage stuff. They will just have to take turns on each act.
And that works horrible on The Voice UK. Marvin pops up so irregularly and inconsequentially that you forget he's even there and wonder if he's been pulled out of the audience...the result is a presenting team that don't feel like they represent the 'voice' of the show at all; but humanoid presento-bots. Talking auto-cues.
Strictly works around the world with 2 hosts because it's an ensemble celebrity cast and you're interested in the group reaction. The two step appraisal process of comments and THEN scores calls for 2 distinct areas, thus a required second host.
The X Factor has no such delineation. There is arguably even less to do than on The Voice. Peter Dickson introduces the judges and then the judges introduce the acts. There is barely enough for 1 presenter to do, let alone 2. But why take my word for it, when they tried it out and it failed on The X Factor USA and the UK the year before last (with Caroline "backstage", which as biffy points out, is horribly contrived ).
The only way it could feasibly work is by not sending the acts backstage after they've performed and keep them in zone in which they could be interviewed as a group by the second presenter as the show proceeds. Like how they did (a bit) with Popstars the Rivals and the Andrew Lloyd Webber shows. But bearing in mind that the show runs to 2 hours as it is in the first few live shows, lord knows where they think they'll have the time...
I think it's right to move on from Dermot. He was completely unengaged with the process. But not sure that 2 is the way to go.