I prefer warrior for three reasons:
1) Hawke is built like a warrior. It's really weird seeing a tall, muscular, athletic mage/rogue who is supposed to have no muscle or only lean muscle training, but who looks and walks and carries themselves like they can pick up a broadsword or sword and shield and go toe-to-toe with seasoned warriors any moment.
2) Since Hawke is not a mage, it's not so much of a plot hole since you're not running around Kirkwall casting spells in broad daylight yet never ONCE have to worry about getting arrested by Templars. At least Bethany gets caught, which is a little more consistent to the "lore."
3) Being a non-mage means Bethany is around and can potentially get taken to the Gallows. That gives any Hawke I imagine incentive to stay in Kirkwall for years on end, since I HATE Kirkwall and can't imagine any Hawke of "mine" voluntarily staying there. It's like, "They've got your sister. You know Meredith's a tyrant and the Gallows are a pit of misery. Better stick around to make sure she's okay." It's also incentive to save the city instead of ditching it since your sister will become Saarabas if the Qunari take it, and incentive to get involved in the Mage/Templar conflict since your sister is caught in the middle.
1., 2. All right, lets clear again ... Hawke do not use his ****** magic in the public streets of Kirkwall, and at the templars. For this to be credible, Hawke has to be strong. Strong enough to be able to fight without magic. Maybe not as skilled as Carver, but he also learned from his father to fight, as it is the first time Carver. Their father was no fool: he taught his children to survive, as it has itself had to stick in for survival. (Yes, Hawke use his magic in the streets, but just for game mechanism, not according to the story.)
Plus, for example from the real life: you dont know people, who smart, strong and well educated?
Lets see one of the evidences!
//indavideo.hu/video/DA2_Qunari_scene; Hawke do not use magic in Kirkwall's streets – at 3:15
.
This is not to say that the rogue or the warrior would be bad choice. Only that: the mage specc for Hawke are not unbelievable.
Ok, rage out, sorry.