Point Walter is fun on an East, and is also good on a NE.
When there is some North, just be careful not to go too far off the spit as the wind tends to feather out.
If your new to kiting, I would suggest you stay on the Northern side of the spit, when you make a mistake (let's face it, you're going to wrap your kite up at some stage, it's going to happen) you don't want to end up floating to Mosman Park. It's a long swim and an even longer walk.
As for hazards, there are a lot of rocks in the shallows, I'd say most people have cut them self's- or scratched up a new board there at some stage in there kiting life. The Northern side of the spit is rockier than the Southern side.
When venturing to the middle of the river, I'd advise you to give way to all vessels, regardless if you have “right of way” just turn back around and avoid a potential drama.
Currents at Point Walter can be quite strong at times, during large tidal ranges (rare) stay north, you won't have a problem.
The offshore side of Pt. Walter is great fun; the wind can drop out so only kite that side if your ability allows it.
Parking can get full at times, I see people park on the gravel up from the car park without too much trouble.
Have fun.
When you get a bit more confident, have a go at jumping the spit.