I think Sakurai tries his best to not be biased about games he made/worked on... sometimes he fails at it.
But his work is not a easy one, it's harder to develop personality and characters into things you do not own/create.
I mean, having Palutena and Pit talk about other characters is easier to be made than make the same with Mario or Zelda, or Cloud. He can't know what this characters would say or how they could react without checking with people that are responsible for them. There's a limit in his freedom that is much larger in franchises he have high influence.
That being said, I'm cool with his bias.
He is a awesome developer that helped Nintendo a lot; gave new life to Kid Icarus and helped popularizing Fire Emblem.
My major problem with Sakurai bias is quite the opposite, his "I personally don't like/experienced this" bias.
It's this that make he underepresent almost everything that is not JP based, as Donkey Kong Country.
We also never got a third-party from a not-JP company. If he wants to add Kid Icarus, Xenoblade, Kirby and Fire Emblem... I'm okay with his.
In my point of view he kind of deserves this. But at the same time he must open his mind to things that are not of his liking or knowledge.