I'd have to disagree a little, Grey.
When the car is easier to drive and on par to slightly faster through corners, it is an improvement!
Because using your exact reasoning... It's pointless to tune *insert road car that handles well with default settings here*, because there isn't much improvement. Improvement is improvement is improvement. I could understand not releasing something because it is still utter dog crap after tuning, but the car being "too good" as a base doesn't really work with me. If it gets better, it is better.
Also, I see a flaw in your logic. Tuning any car is only going to result in so much of an improvement in course time over default settings. So therefore, why do it? :X
But wait... We're all here because we are better at tuning than the general public. So obviously, we tune cars for the public to use. If it fits their style, good, if it doesn't, it doesn't. I'm just a bit perplexed as to why tuning race cars to be even just a LITTLE nicer is seen as pointless due to driving style, as driving style affects how anybody drives any car.
I realize I might sound like I'm trying to be degrading; I'm not. Just curious now.