yes, simply adding 'text' won't make it deep. yes, we should be able to have both, but, with more voice acting we've gotten less depth.
the point is that text allows for much greater depth over voice acting.
it's either that, or, the devs truely don't care about depth and just want to provide the graphics and fluff that brings in the money.
No, it doesn't work that way.
I don't know what this idea that came up everybody's minds, that graphics takes away all money and everything. Yes, they require budget, you know what doesn't require one? Writing!
The studio is smarter than getting people from the writing staff to modelling frankly because that's not their [censored] job, they write stuff and that doesn't even require expensive equipment, so saying how they are focusing more on graphics is just ignorant, when we are talking about a big studio like this.
Again, non of the TES games had deep dialog trees. In Arena and Daggerfall you only just listened what everybody said and at most said yes or no, you could also ask for directions from random people, that's it. In Morrowind you just asked about keywords like "name", "job", "rumors" and the NPC spewed out something mostly from a common pool, so even though all NPCs had uniqe names most of them had no unique line at all.
There was no depth here, no big choices and consequences during speech, you couldn't make the other guy angry by saying something bad, or nice by saying something good, heck most of the time you did not had the choice to decline a quest once you asked about it.
Also there are a number of games out there with complex dialog trees and fully voice acted.
In short, text doesn't allow for much greater depth, because voice doesn't remove anything.