I played a few demos of this at Gen Con, so I'm not a great authority source or anything.
Playing demos means that you're always playing with new players, so I got to see how frustrating it can be as they take their time understanding what they did. But you know, new players…have to give them some leeway. I could certainly see being frustrated with someone with analysis paralysis, but even that could likely be kept to a minimum. There are a lot of choices to make, but decisions are usually fairly easy. I do cringe at the thought of someone with AP rolling 12 dice and looking over four other tableaus in order to decide which action to take. I'd hope that is rare.
I would think the biggest obstacle with new players is that you might not know if they're doing something wrong. This is true of the card game. Whenever I had new players with the card game, I would force a turn order where each player goes through the steps. This allows the new player to see exactly what is happening with the veterans and allows us to identify any mistakes made by the newbie. The biggest one I encountered in Race is someone thinking he can turn in two 3-cost cards to pay for a 6. It's simple enough of a mistake, and it's easy to miss if no one is watching the newbie. And of course if the newbie's mistake isn't caught, then his behavior is reinforced, and he gets annoyed when he's informed of the real rule after he's been playing it that way for a while. So it is I see as a possibility with Roll.
So if I were to own this game, I'd probably want to enforce turn order as well. At least for the first two turns. And the concept is simple enough that I think newbies would grasp it in those two turns. I'm trying to remember if there are any interactions more complex than setting aside a die to change a die face.