It can go both ways really. Yes, if you have a tight development budget and pop a large percent into professional voice acting, the story and dialog can take a good hit, but I have played games with no voice acting and the amount of text was extreme.
For example, although I really enjoyed a game called Inquisitor (not the Dragon Age game mind you) each NPC dialog tree was literally a chapter in a book, no joke.
Personally, I think the way it was done in D:OS was just fine, it gave the towns some additional atmosphere and is on par with how voice and dialog has been done on games like D:OS in the past (and future, Tides and Pillars will have the same partial voice)
But I suppose, in the end, no one has as many friends as the man with many cheeses.
