Why do you think even games tagged as "visual novels" have usually a full voice-over? The text without voice lacks emotion for one. Yes, I know you can imagine all that in your head but it is not the same.
In the games like Dragon Age you can just feel the tension and emotions of the characters with voice acting alone. I sure doubt if that game would be half as fun as it was without it. Also the occasional song sung by the characters could be a nice touch. I still remember the Beer Song from Bard's Tale
...or in DA, that Leliana song was quite nice too.
Sorry, I know I got a little off-topic with all this.
Most games with a lot of text have limited voice-over, like just the first sentence or something. This sets the tone and I find that this is quite often enough (the Infinity Engine games did it this way for a lot of their dialogue)
And just so we're clear, Dragon Age doesn't have a lot of dialogue, it might have a lot compared to current day mainstream cRPGs but really that just goes to show what a sad state cRPGs are in. There are a few sentences at most, usually relatively simple and short sentences. If you want to actually *know* anything about the world you have to read the codex, which is again a lot of text without VO. The amount of replies you can give is also really limited.
If you don't believe me pick up one of the old IE games, and if you want a game with *a lot* of dialogue play Planescape: Torment (if you haven't already).
Also tangentially related:
![[Linked Image]](http://i55.tinypic.com/2eg88ro.jpg)
