I wouldn't say they're incoherent with each other, there's a way events playout with and without Geralt's influence.
They work for a single playthrough, but they don't line up for a combined playthrough. It is not a story you see from two different sides, those are two different stories, and two different sets of events. Saskia poisoning has nothing to do with whom Geralt choses to back in act1. Triss in act1 will talk to a different person through the magic-zoom-thingy, and she does that in a flashback before you made your choice. It makes narrative sense - introducing players relevant in your future act2, but it doesn't make sense as a reactivity to your choice. Not an issue on a single playtrhough, but on repeat playthrough the changes get absurd. I think changing so much, very much invalidates the appeal of choices. You are not seeing results of your action, you are entering different timelines tailor to accomodate your choices. To me Witcher2 became worse after 2nd playthrough.
