A possible solution for the location issues: why not have it deliver to a predetermined booth-like location? Think: Redbox.
Of course, this would be much more valuable if it was set up as a open-source-ish thing (where, for instance, an HOA could set up a "Amazon AirPad" for free). But this would greatly reduce some of the problems otherwise inherent in a delivery system like this, such as (but not limited to):
Apartments (or duplexes, for that matter), pet/child liabilities, cars, slightly-off coordinates that result in your neighbor or your pool being the drop-off spot, highly dense neighborhoods, highly wooded areas, no-doorstep apartments, etc.
Of course, this would be much more valuable if it was set up as a open-source-ish thing (where, for instance, an HOA could set up a "Amazon AirPad" for free). But this would greatly reduce some of the problems otherwise inherent in a delivery system like this, such as (but not limited to): Apartments (or duplexes, for that matter), pet/child liabilities, cars, slightly-off coordinates that result in your neighbor or your pool being the drop-off spot, highly dense neighborhoods, highly wooded areas, no-doorstep apartments, etc.