Well, the server merges have happened and I was just tanking for a group in FT. An instance with only 6 players in it. The lag got so bad that I had to stop and log off. I was seeing lag spikes of 5-15 second duration with 5-10 second gaps between the spikes. We managed to finish but with multiple deaths. On the Kromede fight I was lag-logged for most of the fight. Somehow I still managed to keep aggro. The lag was so bad I was never able to proc my shield skills.
It seems to me that NCSoft may have gone overboard on the server merges if the servers cannot handle these population levels.
Oh, btw, solo PvE play is now impossible in any contested zone. You will get killed by the enemy. They are everywhere now, and they are all in all-gold PvP gear.