I often wonder to what extent voice acting has to do with the limited stories. After Morrowind, gamesas made the decision that every. single. line. of dialog had to be voice acted. That makes it harder to change the story lines, or add more story, later in development, because you need to give the dialog to the actors and producers to record. Something like Radiant Story could be much better if it had the ability to create dialogue without voice acting. Even the hand-written stories could do more if they didn't need so much voice acting, seems like.
You've nailed it, imo. The other day I was watching some "lets play" Morrowind: Tribunal youtube videos and was very surprised at the quality and length of much of the dialogue, particularly from the noble characters such as king Helseth, etc. I remember Morrowind's dialogue and writing as being mature, nuanced, layered, and often cryptic, which greatly facilitated the overall mystical and otherworldly essence of the game. They didn't write dialogue or events as though the characters or world were at all concerned with how well we as the players would be able to make sense of it all, but rather in such a way that simply laid it all out as it would be if Morrowind were a REAL place, allowing us the greatly satisfying and often frustrating experience of learning the ropes in a strange alien world. Everything was thoroughly and beautifully realized from a thematic standpoint, while remaining rough around the edges and obscure, so you never really got the feeling that you know more about the world than the peoples that inhabit it do. And even if much of the dialogue is canned and generic, YOU DONT HAVE TO HEAR THE SAME 3-4 VOICE ACTORS SAYING THINGS THAT ARE ONLY EFFECTIVE (or even make SENSE) THE FIRST TIME YOU HEAR THEM.
Example: things like "Move along outlander", "outlander, what do you want?", or "you NWAH!!!" make SENSE as repetitous voice clips, because they are sufficiently generic. But crap like (and this one makes me shudder... get ready for it...) "Come to dragons reach to discuss the ongoing hostilities, like the rest of the great warriors?" only makes sense once over, after which repeated occurances completely destroy the immersion. Also "You know what's wrong with skyrim these days??". Ugh. Generic crap from GUARDS like the infamous "arrow to the knee" is FINE, because they are GENERIC, stock, faceless characters.
The problem extends beyond the strict adherence to the "must have voice acting for every line of writing" in the game, imo; it's got problems similar to the excessively poor judgments made by George Lucas and co. during the making of the abysmally afwul Star Wars prequels. What really happened is that in trying to make a movie for EVERYONE (ages 8 to 92), they lost sight of what made the original movies so great: they SUGGESTED a universe filled with rough around the edges, gritty, advlt characters and events, yet they could also be enjoyed by children without having to write FOR children. And the effects were in service of the mythical story, not the other way around like it is today.
Skyrim is a great game, with fantastic environments, events, and activities to enjoy. BUT, they have clearly been trying to reach as large an audience as possible, and in doing so are trading longevity and complexity for sensationalism and superficiality (just like everything else in today's media).