And the animation always stays at 60fps. I'm sure N64 games will improve their detail management as time goes on. Another example method is detail texturing, also something which I don't think is used right now in N64 games. Currently, in all N64 games I've played so far, textures blur to a greater or lesser extent as one gets very close to them. Hexen makes this change from one detail to another at a good distance so that one rarely notices the change.
People vary in their sensitivity to levels of detail and the sudden appearance of objects in a game.
Personally, I do not like pop-up and am unimpressed when poor textures are used. As time goes on and the programming techniques used by game designers improve, these problems will lessen. However, it's important to remember that proper detail and load management in the N64 are features that are not automatically taken care of - they are hardware options which must be properly selected and exploited by game designers. So, if a game looks bad, blame the game designers, not the console itself.