From what I understand of the original post, we are meant to be choosing things that are not necessarily "evil" but may ultimately not have the best outcome for the world. So I'm focussing on outcomes that can be considered more "grey" choices.
I would suggest you do the dark ritual in DAO. This is not necessarily the "evil" choice and in fact a Warden could justify it from the point of view that there are only 3 (or 4) Wardens left in Ferelden so if all of them are killed before the killing blow to the archdemon, you've still guaranteed ending the Blight. The downside is you don't know what implications there might be for Thedas down the line when the kid grows up. Since he has the soul of an old god (whom the ancient Tevinter thought were great) and is raised by Morrigan to "respect where he came from", which I don't think means telling him about the Wardens, I'm pretty sure there could be pretty big problems in the future.
Also letting Loghain live when he really doesn't want to (in my play through he was begging me not to make him do the ritual) and leaving him floating around, particularly if you make Anora sole ruler, may well have repercussions, particularly if he knows about Cailan's plan to marry Celene. If he lives the Wardens send him off to Orlais - nice irony and the recipe for all sorts of trouble.
Harrowmount is more of a traditionalist and so the dwarves continue to be isolationists. In the long run this will not be good for them. Don't keep the Anvil so they don't get its help driving back the darkspawn. Essentially you do this because you think Bhelen is corrupt (he is but he does try and drag the dwarves kicking and screaming into opening up to the world) and you don't think any of the current rulers can be trusted with the Anvil.
Definitely need to side with the Templars in the Circle. Can justify this one by the fact that you can't guarantee anyone has not been possessed, even Wynne and Irving.
I would suggest killing Connor because you can't trust him not to do something while you are getting help from the Circle and you don't trust Jowan not to screw up sending someone into the Fade.
As for DA2, just try and take the middle ground on everything since it doesn't make much difference to the grand scheme of things what you do and avoid doing anything that seems obviously "good". I don't really think it makes much difference whether your companions die or not since they are unlikely to figure in DAI but being totally "middle of the road" means you'll likely not end with their loyalty. It may be better not to kill the Arishok since Sten is his replacement and he may well make a better job of it. Don't accept responsibility for Merrill' actions - why should you - and the stupid clan will attack you no matter what other answer you give. Side with the Templars at the end because this seems less radical and you get to be Vicount, even if you're mage, and then Hawke will not have a good reputation among the mages. Suggest sparing Anders because you'll get to kill him anyway but it will really anger Sebastian. May be he will finally get down off the fence and do something but let's face it he's going to be pretty unstable as a result. In fact if you've rivalled Anders I believe you can even get him to attack the mages with you and he then hints he will commit suicide. However, this is not seen in game so may well have left a highly unstable Janders running about the place.