What will kill arrangers as they currently exist is the death of the user base (old fogies) which is inevitably happening. The manufacturers will have to change the product to fit the needs of the younger player. There is some evidence that they understand this when you look at the Genos which is being marketed as a song writing tool with Beth Nielsen Chapman and others. IMO, they will need to make a system of "mix and match" styles using the touch screen to allow the user to very easily create new styles. That would differentiate the arranger from the workstation enough to make it a viable seperate entity.