I understand how to create my own methods that accept input parameters in objective-c but I have never actually created a method with more than one input parameter!
I can think of a perfectly good reason to use NSDictionary to pass arguments. I also believe it answers the question.
You can place all of the items in an NSDictionary then unpack them. This maybe useful if you have say a persitanceStore NSObject that you want to send a list of parameters to.