At the "beginning" of each pedal, I get jerked forward, and then the motor seems to completely cut out until the next pedal. Overall, it doesn't make for a very smooth experience. On my Trek, this didn't happen, and I pretty much was always in the highest assist setting.
I have a few comments - not sure if they're helpful or what you want to hear. I'm also not making excuses for the bike/company, but just sharing my experience.
First, the Current initially shipped with a smoother controller setting. It would keep power delivery at low speeds fairly low, so that the bike would start very smoothly from a stop. A lot of people, including myself, weren't very satisfied with that. Although it's nice and fine for people in flat cities, if you have hills, you will not love low power delivery at low speeds. It is particularly counter productive when you are trying to start from a stop going up a hill, when you will guaranteedly be at low speeds the whole time, but desperately need more power. Other controlers might handle this with more sophistication, but not this one. So, Priority started offering a way to update the firmware to provide more power at low speeds, at the expense of a bit more jerkiness from a stop. It was kind of a nightmare for them, because they had to ship their special cable and sometimes even a laptop to allow users to upgrade it.
I don't know what decision they've made, but it's possible they decided to keep this new firmware as stock due to the volume of people asking about it.
Second, is that I rarely use power level 4 or 5 unless I want to go really fast. Up until 3, I feel the ride is pretty smooth and the total power level is more than enough. At 5, you get a lot of power really fast, which explains what you're feeling. I personally ride at lower PAS most of the time, and only switch to 4-5 if I'm going up a steep hill or want to reach 28mph quickly. I also like to use my gears a lot.
Third is that what you're feeling is probably a consequence of the torque sensor. Again, I am not saying this is ideal, or that there isn't a better way to do this, but this is what I think is happening: From a top, you put a lot of pressure on the pedal. Since you're at max power assist, even as the controller is programmed to give lower power at lower speeds, it's still a lot of power at level 5. That initial jolt propels you forward, which significantly eases the pressure you're putting on the pedal, which the torque sensor takes as a sign to shut off the motor, until you're at the top of the revolution again, putting pressure on the pedal.
I contacted Priority and Truckrun about a throttle. Thuckrun says they do have one for the motor used in the Current. However, they suggested contacting Priority first, due to current shipping issues.
I did contact Priority and they said they do not have a compatible throttle. Soon I will contact Truckrun again and order some. The only issue is that the minimum order is ten, but they are not very expensive. If it works I can eBay the rest.
One interesting point is that, in Truckrun's product listings (think Alibaba) they state that they don't recommend the use of a throttle when the motor is set up for more than 350W. I also think Priority might be concerned that their hubs might not handle sudden power delivery from a throttle very well. No clue, though, just a guess.
What about while using the throttle? Do you have throttle available from a stop, or does the bike need to be moving before the throttle is available?
The Current doesn't have a throttle.
. I'd rather do that than constantly monitoring news that are not encouraging since at least last 2-3 years... Biking is a wonderful alternative to cope, and to lift stress of live 
