Hi DB,
That may be a good personal strategy to position yourself in a contract or even globally as a subject matter expert. If you are deep enough into the end-to-end MM, WM and PM implementations then you will know enough about FI etc to avoid TAX problems, consignment stock holding always involves some sort of infrastructure topics and you can hardly implement anything now-a-days without the SD side wanting to come through from mobile devices to verify stock levels or delivery schedules. You will be fine in the exam.
If you are involved, knowledgeable and experienced enough in all aspects of MM, WM, PM security then you will really be fine to pass the exam, even if you have to take a few guesses on the name of the table for HR Org. Management integration... or take a blind guess that GRC is going to lower your ROI instead of waste your time regardless how you use it... etc...
However if your employer or contracting agency or ego forced you into a little box then it might be tough to have enough breadth and depth of knowledge or experience to pass the professional exam, but that was the same in the old exam as well.
If only interested in GRC and some PFCG things, then stick to the Associate exam. If you are deeper into the topics, including upgrades, integration, authentication options, some Java options, selected coding aspects... then go for the professional exam.
Personally I recommend just getting on with your life strategy if that makes sense for you... Don't let SAP exams get you down if they are easy... ;-)
Cheers,
Julius