Instance 1 on Coruscant and Nar Shaddaa is unbearable. If you switch to 2/3, it fixes the problem. Unfortunately, on Nar Shaddaa, instance 2 is PvP only and instance 3 is full so it's be ganked or deal with 1000ms lag while trying to do anything. I had to log because those options are ridiculous.
Thanks
Apparently BioWare is aware of this issue. Close this thread, please mods.