ComradeJim270 said:
The problem is that, due to the nature of the guilds specific talents, there is very little, if any, logical overlap for faction quests.
The Companions have very little, if any, reason to overlap with the TG, who steal stuff at night, and whose targets are wholly unknown until they attack, or The College, who only goes out of their building to deliver enchanted weapons, or the DB, who kills people suddenly, and unexpectedly, and all means of vice-versa. The TG, and DB, are too secretive, and the College is too isolationist, to interact with each other, or The Companions. It would be very contrived for two factions to overlap, let alone all 4.
What would constitute a non-artificial choice would be something like the Deadric quests where you often have the choice of either
A. killing someone to get some item
B. Not killing someone and losing out on some item.
Like how in Namira's Daedric quest you can take the priest to the ruin so get eaten by the cannibals, and in return you get Namira's ring, or you can kill the cannibals and save the priest, thus losing out on the ring, but getting some gold, and the thanks of the priest.
It makes sense they denying a Daedric lord his desire means you don't get his item, and how fulfilling their desires normally means someone has to die.
Considering that faction systems are forced upon the player, and the player is forced to pick a side in order to continue the game, there is no such thing as choice when it comes to faction systems, beyond which portion of content you want to be arbitrarily denied.
Westside also has a valid interest in stopping the fiends, as the fiends attack Westside often, why couldn't the quest be given by them? There was no reason to froce it upon the NCR, which could allow for players who side with the Legion to get denied said content if they side with the Legion, when said content could be provided for BOTH factions.