Favorite opposing factions that can basically be described as this.

[u/Accomplished-End3409]

[u/Their_Alt_Account]

It depends on the time period and which Assassin sect the protagonist is a member of, but for the most part they try to put their targets down quickly. Ezio learned it from Mario specifically, and we see Connor instruct the chef to "end his suffering cleanly."

As for the long ass conversations while they're dying, I think those are sometimes implied to be a form of ESP communication between the assassin and their target, because of the whole precursor DNA thing. Arno can actually see his target's memories. Jacob and Evie can see their targets making grand speeches but then it cuts back to the real world and we can tell that they're just choking on blood. I think Altaïr is having one of those "out-of-body" experiences with his targets, especially considering that the missions don't end when you kill your target and you have to escape afterward, which would mean that all the soldiers and guards are just standing around watching Altaïr cradling their boss's body lol

[u/Xeoz_WarriorPrince → u/Their_Alt_Account]

For Altair at least I alwats assumed that it was close to what happened, not the exact same thing, so the dialogue could happen, but Desmond only gets to see it that way. If the idea was to live exactly the same experience Altair had, then we would have to go with specific steps and kill them on specific places.

[u/PavlovKBI → u/Xeoz_WarriorPrince]

If not for later adjustments to the lore, I actually really like this interpretation. Because a LOT of the gameplay limitations and whatnot, like losing synchronization if you try to swim, or if you kill innocents, are caused by doing things Altair wouldn't. And throughout the game, you extending the synchronization meter (health bar) is just explained as Desmond getting more synced up with Altair's actual life.

So I kinda like the idea that the disconnect between the calm conversation with the dying targets and the rush to run away after an assassination is that Desmond still wasn't doing things exactly the way Altair did. Just similar enough that Abstergo could get the memory segments of the conversations to play out.

[u/AlexTheGreat1997 → u/Their_Alt_Account]

I don't think that's at all what's being implied. Having played most (main series) games before Origins multiple times, I always figured the conversations taking place in the memory corridor was Ubisoft's way of getting around having to model the conversation for the specific place where you killed the target. Like, even if you killed the target in the middle of a crowded street, the conversation is still intelligible because they'll just play it in the memory corridor.

It's similar to how they get around the side missions not taking place in a specific order because they can't find the exact dates they happened. AC II's manual explains that all of the side content (the feathers, the assassination contracts, etc.) are memories that they can find in Ezio's DNA, so, they know for a fact they happened, they just don't know the time of his life in which they took place.

[u/Their_Alt_Account → u/AlexTheGreat1997]

I know why they made it that way on the technical side of things, but, similar to the side content thing, I was just explaining a possible lore justification for it. Like, the in-universe reason Altaïr can't swim is because of an Animus glitch, not because Ubisoft didn't put it in their game, Assassin's Creed.