Rookies Jackie Shiels and Mairead Kelly were the new faces in the squad having not played in the RBS 6 Nations while Lynne Cantwell returns to international action after a spell living in New Zealand.
But the biggest choice was to leave out stalwart Davitt which Doyle maintains prove how strong competition for places is in the squad at present.
He said: "The one big call was Grace who did not make it because the centres is strongest area of the squad.
"There's new talent coming through and competition is fierce and whoever missed out was always going to be very unlucky.
"She took it very well. I explained my decision to her which she accepted although of course she was very disappointed. The door is still open for her because if there are any injuries then she can force her way in.
"Lynne approached us coming back into the squad and I simply could not turn down someone with her talent and experience.
"She's a real top international. She took a year out of the game and got more experience of club rugby in New Zealand as well as expanding her professional life
"People say the two girls in Jackie Shiels and Mairead Kelly came in out of the cold but I was surprised not to see them in the Six Nations squad as they have been in very good form for their clubs."
Doyle has already been forced into one reshuffle as Ulster prop Lauren Day picked up a fractured wrist and is replaced by Munster's Laura Guest.
Ireland Women's Squad - Women's Rugby World Cup 2010
Louise Austin (UL Bohemian/Munster)
Gillian Bourke (UL Bohemian/Munster)
Orla Brennan (Blackrock/Leinster)
Fiona Coghlan (UL Bohemian/Leinster) Captain
Chris Fanning (Highfield/Munster)
Laura Guest (Highfield/Munster)
Caroline Mahon (UL Bohemian/Leinster)
Claire Molloy (Bristol/Connacht)
Joy Neville (UL Bohemian/Munster)
Yvonne Nolan (Blackrock/Leinster)
Kate O'Loughlin (Clonmel/Munster)
Marie Louise Reilly (Navan/Leinster)
Sinead Ryan (Blackrock/Leinster)
Carol Staunton (Galwegians/Connacht
Louise Beamish (UL Bohemian/Munster)
Niamh Briggs (Clonmel/Munster)
Helen Brosnan (Highfield/Munster)
Lynne Cantwell (UL Bohemian)
Amy Davis (Blackrock/Leinster)
Eliza Downey (Cooke/Ulster)
Shannon Houston (Blackrock/Leinster)
Mairead Kelly (UL Bohemian/Munster)
Joanne O'Sullivan (Richmond/Exile)
Tania Rosser (Blackrock/Leinster)
Jackie Shiels (Richmond/Leinster)
Nora Stapleton (Old Belvedere/Leinster)