In 5th, if it has rage, it must always move full speed directly towards the nearest visible enemy, and charge said enemy if possible. In 6th (supposedly), if it has rage, it can move however it wants, plus it gets an extra attack when it charges.
"Don't get mad, get even", I suppose.
So obviously this makes all units that had rage WAY WAY WAY way way WAY way better than they were in 5th.