One of the reasons I'm really iffy on the whole pre-determined background thingy is that I absolutely hate when rpgs impose emotions on my pc... One of my favorite aspects of Fallout games has always been the ability to be a complete amoral sociopath - an ability hilariously reflected in some dialog choices.
So, either those options will no longer be present, or I'm supposed to believe my evil pc used to be a happy daddy and still cares for his baby, which will kinda ruin his characterization for me.
I can tolerate some none-player controlled emotional reactions in Bioware games with pre-made protagonists, like Shepard or Hawke, but even then certain instances ****** me off - like Shep's cheesy dreams of that stupid kid I interacted with for half a minute at the beginning, whose fate my renegade Shepard really shouldn't give a rat's ass about. I'm hoping for a miracle and that the whole background story will turn out to be a scam or otherwise somehow entirely irrelevant, but with the voiced aspect I fear it may be vain hope.
That said... it's Fallout. Of course I'll buy it, I've been waiting for this game for years. Just please Bethesda, you've crashed my console so many times over the years... at least don't crush my dreams.