I want to be very clear here i am not calling anyone out on this topic, just going to try and be rational concerning this issue.
I am on playthrough 5 right now and as i am an achievement **** i have to have all the different outcomes and thier coresponding achievments. When it comes to whether Loghain lives or dies on ,my first run through i went will Allisters suggestion and exicuted him right there. Then later than evening after the conversation with Rhordian (the seinor grey warden from Orlais) i kind of went oops. Seriously there are only THREE people in the entire country able to put a stop to this Blight and since there would be no guarantee, except excellent writing, that Loghain would even survive the joining. I would be lining up folks around the corner handing out the kool aid like Jonestowne revisited, anything to bolster the numbers from 3 grey wardens to more. In truth i take a very pragmatic look at the situation, it is not about justice, revenge, hell it is not even about what is right, it is about stopping the blight period. Was Loghain a ****? You betcha, but the simple fact still remains there are only 3 grey wardens in all of Feraldin and you throw away an opportunity to add one more? In my thinking that makes you no better that Loghain, it makes you worse than Loghain because YOU KNOW what is out there, it is not a guess for you, you know. Shooting yourself in the foot because you can not handle the fact that he might actually redeem himself by taking the final blow, hell when you take him Loghain eagerly accepts it, he really had Feraldin's best interest at heart, can the same claim be made towards Allister, his stomping off hissy fit pretty much removes him from the friends of Feraldin list. To abandon his post because he can not or will not understand the situation, act in the best interest of Feraldin, makes him lower than Loghain, even considering the grief Loghain caused you. i really wish there was a **** slap option you could use on Allister to bring him back in line.
In the end when you consider what you had to do to get the allies together to fight the blight your hands are not sparkly either. I have left a trail of blood from one end of Feraldin to the other, and would glady do it again, because it is not about me, it is not about Allister, it is not about who is king anywhere it is about the blight. Every decision i was forced to make i justified by invoking the blight. Allister and i have come this far, done so much, infulenced so many things that were not part of our perview, and all of it was done in justification of ending the blight. So when you look at it all, big picture mind you,as much as you may hate Loghain, Allister really let you down on that one there especially after all you went through to even get there.
Anyway as i said i am not taking anyone to task, i am just possibly covering a few things that some folks might have not considered, beleive me i wanted his head on a pike too. I just was willing to wait until after he did not need it anymore.
Asai