One question for you, show, and I guarantee, if you can answer it, it will solve all your problems:
Let's really think about this for a moment. Why did you choose Jack the Ripper as half of your main draw, and then utterly fail to utilize the unique, paralyzing horror of him to drive your plot? Raise your stakes? (All you people concerned about spoilers, do not fear; I only lasted ten minutes into the pilot. Which brings me back to my nitpick...) You have to grip me right from the get go. Hell, you already have me! I'm one of THOSE people, the kind that owns books like Ripperology and movies like From Hell, watched all of Whitechapel the tv series, and is unduly fascinated by the history of Whitechapel's most notorious serial killer. I know a whole lot more about it than I should.
Takeaway: You had me at Jack. And then you lost me because YOU didn't have Jack.
I mean, in the same amount of time, you've got HG Wells down: he writes, he's smart, he's got an effing time machine... He might not be like he was in real life, I don't know, I don't study him. But I'm interested, as far as the character goes. But with Jack, you introduce him with a murder that needs to encapsulate the monster he was... and you don't. Like, at all. Don't mistake me: it's a horrible murder. But it isn't Jack's. There is a reason he was the scariest sumbitch in the area and you did not even remotely capture that.
So I ask again: Why. Jack.
Because you're name dropping? Make up your own murderer then. Because you want the thrill without the actual baggage that goes with it? Make up your own murderer then! Because it would be a bad fit for the somewhat humorous tone you're trying to set? Well, hell. If you're trying to be funny, maybe JtR isn't the guy you need. (Incidentally, is this a kids' show? If so, I repeat: maybe JtR isn't the guy you need.)
So. WHY JACK?
I'm done. I need good time travel stories. Where did 12 Monkeys get to...?