The Isle of Siptah is an expansion to the game. Yes, changes have been made game engine itself. I am not sure on the specifics since they were not shared with me. It was one of the first things I asked when the Closed Beta started.
Ever since they implemented the Funcom Live Services, connecting to servers via the Browser has been awful. My work around is using Direct connect otherwise my Ping is always too high. Apparently this has been fixed on every patch.
Is your issue connecting or playing? If its connecting, try grabbing the IP of the server from Battlemetrics.com and direct connect.
Hopefully this helps. (Besides this being said, I’d agree with your opening statement). I think their priorities are def. in the wrong place. Connecting to servers flawlessly should be a #1 priority vs releasing content lol…