Thunderbolt was not designed to do Mac to Mac connection, it can but that isn't it's primary function.
Target disk mode hasn't been updated yet because they haven't had time yet. It's an old technology, they probably didn't think about updating it when thunderbolt came out because they were so busy deploying other products alongside it.
Give them a chance.
You could try being productive by writing an email or reporting a bug.... Complaining here won't help you.
I just expressed my disappointment. And believe me, I already sent them an email. Which most certainly won't speed up the process, but anyways.
I've been a Mac user for 18 years, so don't worry about giving Apple a chance.
"Is it possible to establish a network connection over the Thunderbolt port" Last i checked Ethernet was a viable network connection
Basically you're right. However what I think he meant, is establishing a network connection with the advantages of Thunderbolt technology:
take a TB cable, plug it into two computers -> start a network. Like Firewire does. With an ethernet connection you're limited to 1g throughput.