My personal; preference would be for another Hawke, if only because it would be strange for the hero to get a strange and unique power once per episode.
Every game has been a deconstruction of the superheroic and pure fantasy hero - the Wardens' power kills them and their order has done terrible things to survive, Hawke is an ordinary refugee who just happens to be good at fighting and can't save the world, and the Inquisitor just lucked into his powers. Having another person just lucky enough to pick up a magic artifact would be pretty dull. It would also slip out of the realm of deconstruction and back into full-blown trope.
The only barrier to another Hawke is Tevinter itself, though. They have three social classes of human mages before you even get to human rogues and warriors. Dwarves are outside their social strata, elves are the bottom, and qunari are likely attacked on sight. The Wardens took everyone, the Inquisitor was (un)lucky enough to be at the right place at the right time.
If we have another Hawke, how would they have any room to manoeuvre in Tevinter? Would they be a criminal? An escaped slave? Would they be an outsider? Why would Tevinter in its arrogance trust a leader of any kind who was from the outside, maybe not human or a mage...?
That doesn't mean it can't be done. But there would be a lot of lore to work around to give us a robust character creature for a non-superpowered hero in Tevinter.