We should really compare the 5-60mph times against the competition not 0-60. This better represents the real-world responsiveness of the car.
C&D measured a 6.6sec 5-60 mph
time. Looks like it pretty much matches the i3 BEV.
Here're two tables for comparison:
In the real world of practicality, there are critical instances when you need rapid acceleration:
From a stoplight when you must change lanes ahead quickly to catch your ramp or turn. This happens when the road signs are wrong, or when somebody is in the Right Turn Only lane next to you and is going straight. If the car to your right does not accelerate quickly you will miss your turn as he will block you out.
Next is the Controlled Metering Freeway Ramps. You are at a stop, and only have a couple hundred feet to merge at freeway speeds.
Last is you are on a mountain 2 lane road. There is a line of cars behind you, and truck struggling to keep up it's speed, and refuses to pull into a turnout.
In case 1, it's 0-45mph you need. Bolt is unknown, but quick.
In case 2, it's 0-60mph you need. Bolt is 6.5s, right up there with many cars in it's price range.
In case 3, it's 50-70mph you need. Bolt is 3.5s, right up there with many cars more expensive than the Bolt.
Seems the 50-70mph testing is not readily available for the i3 without REX, but the REX is not in the same league, even in range added from the ICE generator.
Note that the i3 is more expensive at MSRP than even fully loaded Bolts, yet lacks the other metrics to compete. While the i3 has praise heaped on it for acceleration and handling, it does not exceed the Bolt in any significant area except price.