On a higher level I agree with you. Defining problems, identifying target audience, doing design research etc are all part of the user centered design. If you call these as plays, I agree.
I guess it’s only when we get into more granular level, that thinking plays as a way to solve specific design problems, I start to deviate. All I mean to say is CONTEXT plays a huge role and we shouldn’t be falling blindly for patterns/rules to derive solutions.
I would love to see some examples of how you have used the same play to solve design problems in different contexts.