If your referring the Thermal Expansion ducts, yes those are still disabled with transfer pipes enabled instead, which are quite frankly better anyways.
I know other server have enabled them and I know those servers can have terrible lag at times. We prefer stability and performance.
That being said, whilst ducts are disabled, they are still craftable for quest completion purposes.
As we changed into a Network, we do have to ensure that all servers have a fair amount of resources allocated to them, more than enough to ensure they perform well as before we had only 2 servers running (AS and Yogs) whilst now, on the new dedicated machine we have 9 servers running with another 23 planned, both for our 1.6 network and our upcoming 1.7 network.