As its been said; F&F is seeming like how Kong is in its technology (Which, it should be great for everyone that its being used and not just sitting off the shelf for countless years {Looking at you Disney with the Trackless}), so in theory; it could make people happy.
But, as said; F&F will not be fast. But to be honest; it doesn't exactly need to go fast. I get it, some people want to see a fast racing attraction based on F&F; but that's not necessarily how the film series is anymore when you realize it. Its rarely about the racing, but its about being in the middle of intense action that revolves on the cars, around the hand/gun combat, and any other means that the film-makers (or Comcast for that matter) delves to.
Its my personal rant; but I think that F&F will be fine without the speed, as you'll probably have really good wind effects that makes you think that your actually in the city; but I digress.