When I first heard the rumor about Kingsley and Davros, I had pretty much the same thought. However, if done right, as it was with The Master, I think it could play well. Here's my idea for the story.
At the end of Evolution of the Daleks, Caan makes another temporal emergency shift. When he makes the shift, he winds up coming across a ship that can travel through space. He's low on power and damaged, and knows that he won't be capable of recreating the Daleks, but he knows that the creator can do it, Davros. So, he goes searching for him and finds him. If I remember right, Davros is nothing more than a disembodied head at the end of Remembrance of the Daleks. I assume that he would have missed the Time War, as there was no reason for the Daleks to have both Davros and an Emperor, since Davros would never allow an emperor other than himself.
Wherever Caan lands, he gets some slave labor to build the kind of lab they had in DiM/EotD and basically, "Davros... reborn." Davros gets right to work and starts recreating the Daleks. I'm not sure how the Doctor finds all this out, but he does and he confronts Davros. I have a vision of an episode 12 cliffhanger where Davros, in his inimitable freaking-out voice, displays his new creation to the Doctor, who stands horrified as an army of Daleks comes rolling out of a "warehouse", for lack of a better term.
"I was there when the Dalek Emperor took control of the Cruciform."
The Master said that to the Doctor (won't spoil a thing for any lurker to read that) and all of fandom is asking, "What's that?" We don't really know, but I have an idea. The shape of a Cruciform is really just a cross. But, think about the point of intersection. What if the Cruciform is the point at which all universes converge? It allows anybody who controls it to move between universes at will. The result of the Daleks controlling it would be horrifying.
In Parting of the Ways, 9 says that the Time War was "... the war between the Daleks and the Time Lords, with all creation at stake." It's my belief that the Cruciform was what the Daleks started the war over. When the Emperor took control of it, that was when the Doctor knew the war was over and the Daleks had won. His last plan, the one he knew would end the war, was to focus the Eye of Harmony on the Gallifreyan sun (This isn't something I conjured up, btw, but I don't have a link to prove it, sorry), causing a Supernova that would cause Gallifrey to burn, and to cause all the Dalek ships to burn. That was the action he had avoided all along, knowing he would kill his own people at the same time as he wiped out the Daleks. I suspect that, in addition to The Master being there when the Emperor took, Lord President Romanadvoratrelunder was there also. She would have actually given the Doctor the order to cause the Supernova.
A couple of other things I was thinking about as I wrote this. The only Dalek who figured out what was going on and went into temporal emergency shift was the Emperor. He fell through time yes, but it was of his own doing. The Dalek from Dalek survived because he was caught in the Emperor's wake.
Anyway, in this story, the Doctor himself uses the Cruciform to send the Daleks into the Void and, although the Doctor attempts to save Davros and convince him to turn his genius to something besides evil, Davros doesn't and disappears into the Void as well, which, of course, will kill him instantly.
***spoiler***
There would be no picking up of a ring like what happened at the end of Last of the Time Lords either. As I understand it, RTD did that to leave an opening for the next showrunner if he/she wanted to bring back the Master again.
***spoiler end**
If done right, and RTD tends to get it right more than get it wrong, I think the Davros story could be a really good one, possibly even better than Utopia/Sound of Drums/Last of the Time Lords. And I like those 3 stories very much.
3 episodes to go in this season, next week's had a thing or two that bugged me and is a bit generic, it's mainly just to set up the last 2 shows