Was the F word even uttered in Origins or DA2 at all? I don't really remember.
Maybe a couple times in DA2 but I'm pretty sure not in DA:O.
It was not. And sh*t was never once said in DAO, but got quite a few drops in DA2.
Here's the thing, there's a certain progression to what's alright in games of a certain genre. At the time DAO came out, Bioware probably felt that they couldn't get away with f*ck being said in their game for the same reason they felt they couldn't get away with sex scenes without bras; it's a fantasy game, and regardless of the M rating on the box, there's a cultural perception that fantasy games are for younger audiences.
In the time since, game of thrones and other such series have been helping to break down that barrier. But just because Bioware didn't have the confidence to include swearing or nudity in the first game in the series doesn't mean that those elements have no place in the setting.
Besides, the following exchange is one of the best lines in the game;
Inquisitor: But what can one Grey Warden do?
Blackwall: Save the f*cking world, if pressed.