With the experience he have in the industry and the talent he possess, I can say that Donaire will be deadly in the lower division but the catch is that we must accept that he isn't the Filipino Flash that we used to know anymore as he's already aging but the power is still there, I don't doubt it. But yes, you are right these are just mere speculations and we should watch him first before saying that he should already retire.
If he still wants to get into fights and wants to dominate then he'll do the stepping down. But if not, he'll do whatever he takes before he retires.
Aging really matters in terms of an athletic career, especially in this type of sport that needs physical contact.
But, as of now, we don't hear a lot from him and we still need to wait for the announcement on what his next step.