I think her lust for power is pretty clearly communicated just in DAI. She is not a villain, but she definitely makes herself out to seem untrustworthy. Solas calls her out for it, and I agree with him, she is a glutton for power, but she can barely comprehend the power she seeks.
Actually, in DAI it was the first time I thought otherwise.
I dunno if my local voice acting flavoured it differently, but there was something about her explanation -or rather her rant- about how every bit of history, mythical creatures and ancient artifacts are always found, handled the wrong way and then destroyed, when whatever was awoken reacted hostile in turn. I believed her.
It sounded very heartfelt and genuine, and I agreed. She definitely has changed in DAI and with that, I stopped trying to tame her seemingly aimless desire for raw power like I got used to throughout DA:O. For the first time, she seemed to care about the big picture, and I was inclined to support her views.
It's wonderful what happens to your judgement when you stop trying to get into someone's pants.