Mike Laidlaw recently revealed that neither The Warden from Dragon Age: Origins nor Hawke from Dragon Age 2 will be the player character for Dragon Age 3. It seems like BioWare is trying to keep the Dragon Age franchise focused telling multiple stories set in the world and lore and less about the development of individual characters in it.
Since I'm in a sharing mood, I will put this out there: our intention is that for each major release of Dragon Age, you will take up the mantle of a new character. This does not mean your old character may never appear in future games, but as far as the core protagonist goes, if there is a DA III, it will very likely be neither Hawke nor The Warden.
We want to keep the series about the time and place, rather than about any singular character. While I know not everyone prefers that approach, I believe it's perfectly valid, especially if certain plans of ours to shore up world consistency (import bugs really bother me!) come to fruition, which I believe they will.
And that's all I can say about that.
Thanks to King Cousland @ Dragon Age Wiki for the info.