Long shot since this is such an old message, but I'm trying to wrap my head around this.
Quote: Exactly, you can still do back button AF, then shutter button AE, then shoot.
I don't get this. If you have AF + AE enabled on the shutter button, then when you half-press the shutter button, you do get AE lock but you also lose whatever focus you might have set with your back button. No?
Or do you mean that you do back button focus, keep that button pressed, then half press your shutter button to get the AE lock, hold that too if you need to recompose, then finish pressing the shutter button to take the shot?
Or, as awkward, first do the AE lock with a half press shutter button, hold that while focusing with back button, then finish pressing the shutter button.
I know that since then there's a a feature to tap the scree to do snap focus, but I find it harder to frame that way than with the full press snap when shooting from the hip.