Narration cannot be separated from level or system design, imo, and camera angles are a big part of that. As an example, there are certain vistas and moments in Fallout 3 and New Vegas that could not be accomplished without breaking you out of the isometric view regardless (REPCONN rockets launching). You can't get the full impact of weather, day/night, seeing the moon over Vegas, seeing the two Ranger Statues in the distance at the Mojave outpost, seeing distant flames at Nipton, looking up to see the Goodsprings cemetery with the skyline of Vegas behind it, or seeing the storms of the Divide to complement the location (the last four of which I'd argue are strong narrative moments as well as superior level design touches that cannot be done isometrically). I feel isometric is great for multi-party (like, 5-6 individuals you're controlling in combat), but when you're the lone wanderer with one or two companions that take general orders, it's not essential.