It is weird that "hold" doesn't make them immobile forever. When I pull a mob in, they all move slightly, especially the warrior. You'd think they would just stay in one spot.
However, it does seem to prevent them from moving 30 feet away just to cast that heal like they were doing before. Nothing I hated more than the cleric running past the mob for whatever reason, only to stand in the path of the add I was trying to avoid. This seems to have mostly remedied that, which is good enough for now.
Somewhat related, the VERY FIRST time I used the hold command was when I logged back in after the patch last night, in front of the Twisted Haunt by the Renewal Sage. Like always, I pulled the earth elementals over and went about killing them, checking how the hold command was working. Apparently I targeted the Sage though and she one-hit killed me. I had no idea what happened, and I was trying to figure out if somehow I held the healers too far back or something. Only when I checked the combat log did I figure it out. And of course the rest of the party must have attacked her as well so I had to rez them all.
I feel like there are a lot of npcs you can't attack in game, but maybe I'm wrong and everything is open season? My fault, obviously, but just weird that they even allow that one.