I've heard that before, I wouldn't be surprised if it truly was said, but I find that to be nonsense.
There are GBA games with much more impact and success than KI. Pit either had to be on a prior list of considered characters with the port maybe clinching it... or the pool of games out of which KI was only as wide as all the other retro re-releases, because Sakurai was seeking a retro character. Or it's a false statement.
Checking.
There you go,
it's the second. I personally would be unsurprised if the first also played a role. Though if anyone has a better source please share, because this guy didn't cite his sources very well. I stand by ports being of little consequence, however as it is with retros, in the land of the blind, the one eyed man is king.
Further checking.
Hey look, it's also the first as well. Ostensibly, Sakurai was gauging the most popular retro at the time via sales numbers.
Wait.
Ok. And now, to complicate things and throw the whole claim into question,
KI was the second worst selling NES GBA port. Fwiw, this is also the only actually sourced claim, though the link has expired.
So idk man...