First of all, he's a workaholic. He already has health issues and with this lifestyle, it can only get worse. He seems kind of insane in that regard because he doesn't seem to realize it at all. Worrisome.
There's also the fact that he originally planned to not do all the balancing on his own, he went out of his way to say this in an interview so he must know that that was probably one of the biggest burdens during previous Smashs' developments.
And here he is again, doing it all himself. I understand the logic behind it, it seems reasonable from a game quality standpoint, but at the same time I feel like he probably hates doing it but would go crazy if someone else were to touch it. Literally insane.
It's also funny because I do think he actually has a wife, at least he had one in the Sora days. But every few years he's moving for 2-3 years, leaving his wife/family behind (he already moved during Brawl development for the same reasons). I'd love for him to talk about that, is that just normal for them, is it just "well that's how our life is, no big deal"?
And stop worrying about his balance comments. He balances based on 4 players free for all matches with items on. Always did. So the end result is completely unpredictable.
And even if he tried to balance according to what the competetive scene wants, you can't guarantee balance.
He actually might even fail if he were to try to make it imbalanced on purpose. It's just out of his hands, ESPECIALLY the way he does it.
Hundreds of enthusiasts dissecting the game for YEARS will always create a product the developers did not intend because they have neither infinite amount of time, nor as many people. There are awful characters and there are very dominating characters in every game no matter what, so props to him not freaking out over it (even though he's probably not as aware of the whole situation in the way I'm describing here, different perspectives and all).
I'm not saying "ignore balance", but neither is he.
I do not keep up with P:M much, but at what cost is it trying to achieve close to perfect balance (I assume that's what you're getting at)?
They release new versions relatively often, making slight or not so slight adjustments every time, partially based on feedback from the community (again, I assume it does have some influence) for ... as long as they want?
This is not an option for Sakurai or any huge official game like Smash.