I would, in turn, argue that because Fallout New Vegas and to a certain extent Bioware games are examples of good RPG voice acting while not skimping on choices, Bethesda has really run out of excuses here.
The best solution, to me, would be to stop trying to make every single character unique because by doing so you drag down the quality of dialogue for the characters who are actually supposed to be unique. Instead, decide on a select few characters who will receive good attention, spend a lot of time making them stand out from the crowd, and just keep the generic NPCs generic. This is what Obsidian did, generic NPCs would only give you a quick quip before moving on while the characters that mattered were fleshed out and well realized.
Bethesda just tries to make everyone well realized. And as a result, the dialogue gets hamstrung. Makes since too, considering how muddled Skyrim's stories were. In short, they were trying too hard.
Except I saw lots of people complaining NPCs in towns were too quiet and didn't have the background conversations heard in Fallout 3. Let's be honest - if the NPC pvssyr was cut from Skyrim, people would be complaining it ruined immersion because the towns would sound too quiet and nobody says anything except you. I'm not disagreeing with your point because I think Obsidian's dialogue tapdances all over Bethesda's, but unless they double the amount of dialogue, people will complain something is missing.
However, I think it's not so much the quantity as the quality - Bethesda do not write very well and could use the dialogue they do have far better. FNVs characters weren't so much the amount of dialogue, it was they were very well drawn - just compare Cicero to No-Bark Noonan or Fantastic.
I personally would rather have no guards commenting on my skills like "hands to yourself sneak thief" and more on my race. My current dark elf character has - I was pleasantly surprised - had a few bits of unique dialogue based on their race. But not enough. I'd like more of that.
This talk of text only is IMO totally barking up the wrong tree - it's 2012 - computer games have talking - Bethesda are not going risk their immense sales by going all retro and turn Whiterun into a silent movie, however critically acclaimed that new silent film might be.