You mean stabbing Anders? He is not beheaded. And people feel betrayed because the game doesn't let you choose the outcome. Anders is the flip side of Isabella. Both betray you, both wind up plunging the city into flames. But that little twist in the writing and suddenly you are outside of the events, nothing you do can change it.
I hated more that there were 3 year time jumps where apparently Hawke just went to balls and drank tea instead of trying to do anything to improve the state of the elves, mages, Ferelden refuges, nothing. Clearly horrible abuses were going on, but Hawke didn't do anything about it.
Go back over over the game. Look at your companions, look at all the events Hawke went through. Consider that you are drawn to people who have the same level of darkness in them that you do. Bearing that in mind...maybe Hawke is crazy? The choice of companions does not bode well.
Indeed, stabbing. Sure, Isabela betrays you, too! This topic isn't about Isabela, though
Depends on my playthrough on how I treat her in the aftermath. I personally get irate at her actions as well.
The time jumps irked me for many reasons. Your point is one, the other is that there is no obvious signs of time passing. No change of clothes, no changes in scenery, no new vendors... nada! There's a mod that changes NPC clothing in between acts on the Nexus. Thank gosh for it.
Hawke's blindness, whether on purpose or not is irritating. You'd think she'd have more insight/intuition (especially as a mage) when you do his quest to obtain the ingredients for the bomb. Perhaps if you found out and stopped him, it would be too late as it was given to someone else? Not sure.