I love Hikashop - it can do everything most people want from a shopping cart and it is a pleasure to use.
However, the lack of documentations sometimes drives me to despair - I know it is all possible but I just can't find how to do it.
You are right, it has many features now, and many possible scenarios are covered - such the may ways Shipping tax can be calculated for example.
But I think just documenting what each data field does on each section of the application is not enough now.
There needs to be documentation/tutorials that link the sections required to perform common tasks - for example:
manual shipping with shipping zones and shipping tax, or
the process of creating an affiliate, creating banners, tracking sales and paying commission.
May need to hire someone to start adding this type of documentation, it would be a huge boost to the product and it will save users many hours of finding how to configure one area and then finding things are not working because there is another area that needs to be configured &etc.
Saying all this, I will still champion Hikashop and the amazing support team.