** SPOILERS! ** If you are going to do another run through with making Loghain a warden then I would advise you to harden Alistair and have him marry Anora. This is the best way to save Alistair, he will hate you and you will destroy anything you had with him as a friend or otherwise..but honestly it is better than the alternative. Alistair is a good man and he does not deserve to be betrayed, so to me this is the best option for you. If you do not do that then you will have effectively destroyed Alistair if you allow Loghain to live. Also you need arrange their marriage with Anora before the Landsmeet, otherwise she will not agree to marry him and want him killed to prevent him or anyone else raising an army in his name against her. I could not in my heart do that to Alistair. To allow Anora kill Alistair or to destroy Alistair, no this will never happen in my play through. Alistair and I have been through hell and back and to turn on him at the end felt wrong, IMHO. You will also need to make sure you cover all your bases where the entire Landsmeet to be on your side, this will also prevent Anora changing her mind. Anora will turn on you if you do not make arrangements with her first.