The clutch was nerfed in GT5 Prologue about ten years ago (
see original thread). Before the nerf you could flat shift/power shift & you never missed any gears; you know, just like you can in real life. After the update, you had to come off the throttle to shift, otherwise, the game just threw you into neutral. You also had to push the clutch down a lot further to shift, otherwise, the game threw you into neutral again. This made it not only unrealistic but also extremely frustrating for most people to use the clutch & h pattern shifter. The exact same poorly designed & deliberately broken clutch model seems to have been copied & pasted into every single GT game since, including GT Sport.
The underlying problem is the incredibly stupid way certain people at PD "problem solve". Instead of fixing the loophole their bad game design by disallowing the use of both paddles & h pattern at the same time, & by changing the paddle shift delay on all cars to match the average h pattern shift time, they decided to break the clutch everywhere in the game instead. Ten years on & they still haven't learnt their lesson & have applied the exact same thoughtless & hurtful "solution" by nerfing the clutch some more.
The new "solution" in this update to disallow clutch in Sport Mode is also a pretty stupid decision as well, because, Thrustmaster T-GT owners who liked using clutch & h pattern in Sport Mode can no longer do so. Not only are they hindering sales of Thrustmaster add on products, such as their shifters & pedals sets, but they also seem to be on a mission to destroy the gaming experience of the customers of their official licensing partner Thrustmaster, not to mention all other clutch users. Also, when you turn on fully adjustable gearing, you cannot use the clutch to shift either (you could do this in GT5, but not from GT6 onwards). All this smacks of thoughtless, lazy, & utterly poor game design decisions by PD. It makes me wonder just how many Thrustmaster shifter/pedal sets have been returned over the years as "faulty" because of this...
If they simply do these four things, mentioned over & over again by the GT Planet community on these forums, it will solve all these problems:
1) Un-nerf the clutch; no more miss shifts/no more being thrown into neutral, no more pushing it all the way down to change gear.
2) Speed up the shift time for paddle users in all cars to match the average shift time of clutch/h pattern users.
3) Disallow the use of paddle shift & clutch/h pattern at the same time (to stop cheating via exploits).
4) Allow the use of clutch & h pattern when fully adjustable gearing is being used.
Now, paddle shifter & clutch users can compete together in Sport Mode & open lobbies with no real advantage or disadvantage to the other. Now, Thrustmaster customers who've spent hundreds on a T-GT & shifter & pedal set, can drive in all game modes & in all cars with or without fully customizable gearing using their expensive purchases. Now, everyone is happy.
Despite their collective genius in making the Gran Turismo series, sometimes Polyphony Digital can't even think their way out of a wet paper bag!
EDIT: Giving controller users access to the clutch via the analog buttons on the DS4 is way overdue too.