For me my main top GTN annoyance is the GTN it self. It is so messed up dealing with it just to sale our products. I wish we had our own Vendors that we could use.
At some point your Legacy can get the GTN on your ships, I can't wait!!!!
My biggest gripe about the GTN, Speeders pushed right up into it. Why do you need to be on your speeder when you are doing business? Do we just have way too much drive through mentality these days? Please, Please, Please, get off your speeder when you pull up to the thing, it's a small enough area as it is.