We're currently investigating the lag issues with Sins multiplayer and have some good leads. If these pan out, the updates will be backported to Trinity/Diplomacy....
It is fixed?! The lag is gone!? Today, I noticed that it is faster! It logs on, and lists games much quicker for me. Maybe the downtime was used for repairs? At least, I can say with confidence, that I can get online, and into chat, and see who's there, and which games are available, all much, much quicker than I have been able to for months (ever since 1.2 came online).
So that looks like progress... but as I type out chat, it appears erratically, like its still laggy. So I don't know yet, if the lag is all gone?