I'm pretty sure it will sell below Mass Effect on consoles.
ME was rpg lite well adjusted to mainstream gamers.
Kotor 1 with Star Wars fanbase sold 2M.
DA which is more of NWN/Kotor mix and lacks well known universe will sell 1-1,5M on x360.
And with no Bioware game released on sony machines previously I estimate PS3 version will sell 300-500k.
PROUD MEMBER OF THE PSP RPG FAN CLUB