Draxxan, now with fellowhip system, there is no more reason for upgrading the Trader: in a fellowhip you've a lot of cheaper offers so many problems about that have been succesfully solved
The idea to be able to upgrade the trader or to develop the trader by research, has been discussed respectively here (click) and here (click). Please add your ideas and support to the thread you like! I'll close this thread as a duplicate.