You raise some good points TLR.
In my own experience, I find the front of my RK 'whippy', if that makes any sense. At speed I find the front end is slow to respond to inputs, and when it does it is late and seems sloppy.
It could be the forks, I can't say, and you make a good point when you say it just might be somewhat pointless to change the upper part of the TT if the bottom one sucks as well. And, let's say it isn't the fork legs, it makes sense the lower clamp has to handle some big loads, maybe even more than the top, given the lower clamp sits in the middle closer to where the loads are being generated.
Assuming that someone has maybe done some homework, and has arrived at the top clamp being 'the weak link' so to speak, one look at the replacement part and it's huge amount of overlap on the fork leg compared to the stocker, it's no surprise it would make a difference. Whether the stock one is adequate, and hence replacing it pointless, is the question we're asking.
The decision I made to replace it is simply based on this 'whippiness' I feel. I'm not that far removed from modern sportbikes, and they sure can't be accused of being whippy or sloppy. Of course, clip on style, short bars don't allow generous inputs we can with long bars. (of course, not required on those bikes to get 'em to turn with the difference in the geometry of the two)
On my bike I can simply go out on the highway on a straight stretch at those speeds to easily initiate slop, and I'm attempting to reduce it. I'm an old bugger and when I want to go reasonably quick on tight roads I don't like scaring myself as often as I do now.
Granted, maybe expecting to eliminate the slop from a 700+ pound bike is pointless anyway. We don't buy Harleys to tear up corners.
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