I never thought Akiyama was undersized for MW. I suppose he could make WW but I think it would be a hard cut unless he changed his body and lost some of that muscle. He might not be the tallest MW but he's a thick well muscled guy. I think he just needs to do some altitude training and work on his cardio.
On the other hand, it could be the amount of muscle he has that makes him gas. That's a lot of oxygenated blood for all that muscle. I also remember a quote from Bas Rutten in a recent Pride FC tribute article where he said a six pack or large abdominal muscles are bad for fighters because it restricts the diaphragm and prevents the lungs from fully inflating. I never thought of that, but it makes sense.
So I guess I don't know whether he should or shouldn't, but I do know that it isn't up to us anyway