I've shown you this list before, but since it seems like you're in similar territory, I'd figured I'd drop a link again since there are a lot of share ideas here.
http://tappedout.net/mtg-cube-drafts/rise-of-the-rise/
Some thoughts from my experience playing this with some friends.
It can be extremely daunting for even experienced players.
If you don't open one of 10 or 15 significant 'goal-driven' cards, picking a direction can seem like shooting in the dark. I've found some players don't like this.
As my fellow designer put it, "it needs more Spectral Riders". Maybe there's such a thing as going too deep with synergies and good baseline creatures are needed to insure the game progresses at a steady pace. This idea is turning out to be a rather complex one.
Surprisingly, games often lack interaction. This could be related to the above idea.
In general, it suffers from the same problems that Future Sight is often associated with.
A thought on your list.
Including Prime Time and Ghost Council seems like a huge error. These cards are so absurdly above the curve of the rest of the cards that they actually invalidate your basic idea. I pulled the Bringers from my own version for this reason as well.
I don't feel the same way about Ulamog, as getting to 11 is on par with the basic idea of the cube: establish a goal and successfully execute it.
Clearwater Goblet is an incredibly unfun card. It's unbeatable for aggro decks and comes down pretty quickly. I'd highly suggest against adding it.
I found domain to be pretty shallow as a theme, as it doesn't interact with much else.
I haven't focused on this cube since Gatecrash came out, but rather have taken a couple lessons from it to my more traditional cube.