I haven't finished Act 1 with an Origin Character so can;t comment too much. I understand why the MC is always silent, and I understood very, very rapidly how that affected my Origin play...
.. But I'll stand by it that they work much better as NPC companions than as a Player Character. And the weirdest thing is, is that many of the unique content, you just get while controlling a non-player Origin. Say, entering the Goblin base whilst controlling Shadowheart - you get the whole 'You feel this and that about Selune', and it follows by her speaking up to the Main Character about how she hates the place.
ANd, knowing this, I now often select a companion whom I suspect mioght have something going on in certain places. BUt suspect I'll never do a full run *as* an Origin.
