The only disadvantage of Donaire's age is his stamina not his speed nor power, no one can doubt that because his oxygen tank slowly depletes as he grow older and so does the other boxers. What he lacks is the stamina to go all the way until round 12 without getting so weary because Inoue can still dance in the late rounds and that's the time where Inoue will summon all his strengths to take down the aging Donaire, I agreee Donaire's only choice is to be more aggressive and more accurate in the punches in the early rounds.
It is such a shame that we do not get to see Donaire fighting at his prime otherwise this fight could have a great chance of becoming the fight of the year, but still it is nice that we get to see the fight happen at all, and without a doubt the biggest obstacle for Donaire to win this fight will be his stamina, Donaire needs to accumulate enough advantage over Inoue during the first 9 rounds of the fight and if he cannot do it then Inoue will most likely win the fight by taking advantage of his superior stamina.