I believe that the show is definitely a story of two timelines. I apologize in advance for the length of this post. Please bear with me here.
Timeline 1 (the main timeline) is the baseline. Let's call it "the present" - or T1. Timeline 2 is the "past" - or T2
I have noticed that some characters only appear in T1, and some only appear in T2. Some appear in both timelines. AND THERE IS ONE SPECIAL CHARACTER, who appears in both, but may not be the same person in both timelines (I'll get back to this).
William and his asshole future brother in law are in the past/T2. This is indicated by the dated Westworld logo, and some other slight indicators (as many have pointed out).
Teddy Flood, most notably, only appears in the present (T1). If you notice, the "Bounty Hunter/Gunslinger" who invites William to go "huntin' desperados" is NOT Teddy. But he appears to be filling Teddy's role.
The man in Black also only appears in the present. William and MiB (if I'm correct) will never be seen together. Sadly, I think William becomes the MiB. I say sadly, because they are both interesting in their own right, and the time will come when the story becomes only about the MiB. (Also, Awww. William gets corrupted?)
Here's where you'll say "But, but, what about...?"
It all hinges on this: DOLORES IS NOT A RELIABLE POV CHARACTER. This is important. Some of her scenes actually fluctuate between T1, T2, and places in between (more below). Sometimes, it isn't even reliable who she is looking at. This is particularly in scenes that she shares with other characters who have existed in both timelines.
"But her conversations with Bernard..?"
I believe that her conversations with Bernard are occurring in BOTH timelines, and because of the unreliability of her POV, they are presented to the audience as several unbroken conversations. If you pay attention though, in at least one of those conversations, Bernard's tone, mannerisms, AND WARDROBE - all fluctuate. In fact, it starts in T1 (where he agonizes about reverting her), switches to T2 (when he tells her to leave), and back to T1 again (where the deputy tells her about Teddy being stuck out in the woods with the crazy murder people). The scene then switches back to T2, where she shoots the baddie, and runs into William and The Asshole.
I believe that this is because we are not watching a story of the dawn of AI self awareness. We are watching the story of TWO instances of AI awareness. Both instances involve Dolores, and because her memory is unreliable, her scenes switch freely between timelines, and she also sometimes isn't fully aware of who she is interacting with. Dolores causes the "catastrophic failure" of thirty years ago.
Bernard is my "special character". Bernard in T2 (the past) MAY NOT BE BERNARD. There are two possible explanations for this, T2 Bernard may actually be Arnold. Now this is where I get a little fuzzy - because I don't believe that Bernard is an exact copy of Arnold. Rather, (Possibility #2) I think he is a host that was given some of Arnold's personality and backstory - enough to make him follow in Arnold's footsteps. If it turns out that this is true, I think that we as the audience are being presented Arnold in the guise of Bernard because Dolores CAN'T TELL THEM APART - or she's confusing them in her unreliable memory.
Pure conjecture: I think Dolores massacred everyone in the park, and William stopped her. And in return, he was given lifetime carte blanche. And he spent thirty years of his life trying to get his revenge for them stealing his innocence and dooming his girl to a life of servitude. So. The crux of my theory is, Bernard is not always Bernard. And Dolores isn't always where we think she is. And we're watching her awakening to sentience TWICE.
- The park is on the moon. In "The Stray", Not As Pretty As The Other Two Hemsworth mentions that the stray in question may have "gone moon mad"
- "But the early host models supposedly sucked" Ford says that by the end of the first year, they had passed the Turing Test. Guests did not arrive until two years later.