The stock throttle mapping is horrible which has a lot to do with the sluggish feeling IMO. Even the Raptors feel this way.

Proof: Punch it at around 60. It will drop to 3rd and take off pretty well for a 7300# truck. It won't ever have the tq of the diesel to where it will accelerate by rolling into it, but a tune will improve throttle response more than you imagine. That's next on my list.