We dont see it as an issue. Heaviest regen comes in when the brake pedal is used, otherwise the initial regen can be controlled by use of the right foot. This is a common issue with all EVs many drivers expect them to work like an automatic vehicle where you mostly coast with no power, and it shows up that drivers spend a lot of time on and off the power. Here in the UK fewer drivers have autos so we are more used to driving an manual vehicle, if you are up and down on the throttle all the while, it just doesnt work. So I guess we find it more natural to drive an EV (Hisun / Polaris included) in a more appropriate fashion not expecting them to drive like an auto.
The Degree of regen and the brake pedal regen can be adjusted. I have only done this once for a customer.
The latest E1s dont use a Sevcon, and the software to do anything, just isnt accessible. Even the importers version is limited and the software is entirely in Chinese.