How come I can join the Companions, Thieves Guild, Dark Brotherhood, College of Winterhold, and Dawnguard/Volkihar Vampires and not get any problems? I mean wouldn't you be barred from the Companions if you were a member of the Thieves Guild, Dark Brotherhood, or Volkihar? And I doubt the Dark Brotherhood would take kindly to a Companion.

If you ask me, they should have made it where if you went the Warrior route, you can only join the Companions and Dawnguard or just the Bandits. And make the College of Winterhold exclusive to Mages and etc.

Companions would kick you out, possibly kill you (doubt it)
Thieves Guild wouldn't care, especially when dealing with the DB since they both already are familiar with each other. Bring in coin is all you need to do.
Dark Brotherhood wouldn't care, same as above. They already have a former Companion, even then he doesn't care that you are with them in the first place.
Dawnguard wouldn't care so long as you weren't worshipping a daedra. Though they'd have problems with you if you said you worshipped the Night Mother and Nocturnal.
Volkihar definitely wouldn't care especially if you are the baddest vamp of them all.
College wouldn't mind so long as you didn't steal from/kill fellow students. If you were a vamp or wolf they'd just be interested in you.

Nope, it's better the way they did it. And if it's known by other guilds that the character is in either the thieves guild or dark brotherhood then the player is doing it wrong anyways.

I agree. There should definitely be restrictions.

Well, if you're looking for depth in vanilla Skyrim, then you're in for a hell of a ride.

It would certainly make it more realistic and believable, but you wouldn't be able to experience everything in one playthrough...
Come to think of it, that is actually pretty good!

Who only doe one playthrough anyway? In TES?

I would have liked to see some mutually exclusive factions, but with the very few amount of factions we have left I think that might be counter-productive.
It would be good if we had a decent amount of factions, such as Daggerfall and Morrowind had.

However, what irks me about Skyrim factions is that they exist in a vacuum.
They do not connect with any other storyline and faction and the civil war and the return of the dragons may as well happen on a different world entirely as far as the Companions, College, Thieves Guild and Dark Brotherhood are concerned.
One would think the Companions and College at least would have a part to play in those two major questlines.

Skyrim factions exist as quest-hubs, nothing more.
That almost no NPC is well fleshed-out and that there is no well written faction storyline with decent pacing and a statisfactory ending also really does not help.

Yeah, you'd think the College of Winterhold would be important to the main quest because they would definitely be researching the return of the dragons to try and determine a cause and there's no doubt the Companions would be integral because you'd expect them to lead a divine war against the Dragons