No where does Daishi say he's going to intentionally unbalance SC5. You're all miss quoting him.
"....And Street Fighter IV was really well done-certain moves would cause a lot of damage, and the balancing was quite interesting to someone who's interested specifically in fighting games. That balance seemed to change when they introduced Super Street Fighter IV, though; the game was, of course, more balanced as a whole, but it lost some of its uniqueness, I guess? Personally, I thought it was more interesting before."
There's also a concept in Japanese called wabi-sabi, which means "a perfect balance between too much and too little." So, it's not like you can just make everything over the top and it'll be OK; some elements have to be kind of bland on purpose. [That even goes] for character; Some can be strong, and some we want to be kind of weak, on purpose. That's a perfect balance from the Japanese mentality."
I can clearly see where Daishi is coming from and it's not something as simple as an unbalanced game is ideally better than a balanced one.
From SF4 to SSF4, I personally felt because of the larger roster, and better balance the game lost something. Daishi calls it a lack of uniqueness. And that's something that I would say exists in T6 as well, despite the game being balanced. The characters don't standout at all. The roster is larger but to maintain that balance the characters come off very similar. Even though the animation or fighting disciplines are different the moves perform the same tasks with the same power.
The trick for designing a competitive game is, the smaller the selection the easier to balance while maintaining the uniqueness or distinction of each character. The larger selection, makes it harder to balance without basically cloning everything.
In SC some characters are good punishers, some characters have incredible ringouts, some are faster, and some do massive amounts of damage. And also unlike other fighters the weapon disciplines personify the characters. I feel the balance Daishi is talking about lies within these distinctions. Not overall competitive balance, as in 7:3 match-ups and such.