Have you actually spent any significant wheel time with a Fit?
Yes. And no, there was no real chassis balance, no ability to throttle-steer it, and nothing more than safe, predictable understeer. At low speeds and below the threshold of traction, it's not bad, but when pushed, it just understeers away. Honda can't sell it any other way, as it's not a performance car, and is for mass appeal.
Stickier rubber would raise the limits, but not change the behaviour of the chassis.
Yes, for most people, it's more than enough, and at legal and even quite illegal speeds, it's fine. But, compared to a fine RWD chassis like an 135i, it's not great. I know the BMW is much more expensive and not at all designed for the same purpose of the Fit, but the BMW is a truly incredible handling car that combines a near-luxury ride with superb handling.
It's all relative. I'm a pretty good distance runner in my age category and my little city. But, stacked against the best, I suck. I'm not really that fast, regardless of how great I look in some local amateur event, and I know it. When someone says the Fit is a great handling car, I think "compared perhaps to a few others, but actually, it's not."
I'm not shitting on the car. I highly recommend the Fit to people all the time. It's a great package and I wish people would abandon their stupid SUV's (compared to which the Fit drives like an F1 car) and realize that incredible utility can be found in economical products.