Mythic decided to be a little sneaky about something on the PTS event yesterday. They turned off friendly player collision and didn't bother to tell anyone about it until afterward. The Core Testers already knew what was up, but when asked for feedback about the test, no one else could jump and say that friendly collision was turned off. Almost everyone saw performance improvement, some massive improvement. There wasn't a single negative comment about it before Andy dropped the bomb on us.
Note that enemy collision was still on the entire time. You just would not get caught up on your realm mates.
After the news was given, some players brought up concerns about the tank wall no longer working. This is only partially true. The shield wall simply has to evolve to the phalanx.
For those unfamiliar with a phalanx, it's basically two or more rows of shield tanks with third or greater ranks being DPS. The way the tank wall currently works is that you need 5 seconds to push through the enemy and then 5 seconds to push through your ally to clear the wank wall. With no friendly collision, you need 5 seconds per rank to push through. A 2 rank deep phalanx covers the current job of a single rank tank wall.
The phalanx is easy countered by a flanking maneuver much like a tank wall. The players will have to modify their tactics to play in this new environment, but overall I think it will be good for the game for many reasons.