Since this book will be advancing the DS9 timeline to 2382, I think DRG3 is probably the best person to tackle it. It will probably be really long, but will in turn please DS9-R fans as they will have a thick tome to ease their minds about the 4-5 year jump.
I don't doubt that it will please a lot of fans. Though I don't like his style, obviously lots of people do. I, however, think he's exactly the wrong author to write a story that spans a long time, when he gets so bogged down in the details of a scene. In my experience, his books are long because they use so many words to describe things that can be adequately, heck, even well described, with half the words he uses. With how long it can take him just to get into a particular scene, I can't imagine how he can string together enough scenes to make a 4-5 year story seem coherent within anything approaching a single novel, unless I'm misunderstanding the approach he's taking in the novel.