The only real basis for any type of change, is that these are wild animals, and their population numbers. One of the posted articles, I think reef's said that Japan allows up to 20,000 annually, and about 1,300 are taken annual at 'The Cove.' That seems like a lot for a slow reproducing, near the top pf the food chain animal. My guess is that while that may seem like a big number, if the Japanese were hurting their population numbers, we would be hearing about that, instead of a weaker argument of how intelligent dolphins are.
However, if it's found that they are decreasing the population, regardless of any heritage/cultural meaning, then something must be done.