Add an option to enable fast running animations from older versions(ParCool!3.3.x.x's fast running has severe shaking in the first person perspective,but 3.2.x.x is well.).Then,the head of the third person animation need move forward with the body during fast running.When rotate the perspective during fast running,the third person animation should have a smaller head tilt angle, or not tilt at all.
Allow the player model's head to freely rotate with the perspective during sliding and crawling.
Add animations that standing up directly from sliding, instead of switching to crawling and then standing up.
Real Camera:https://www.curseforge.com/minecraft/mc-mods/real-camera
Other suggestions:
A option: Nothing can stop the fast run unless the player releases the forward button.
Larger horizontal wall running perspective rotation angle(90°),moreover, is it possible to implement a horizontal wall running operation similar to Mirror's Edge? The entire operation can be completed using only the space key.
A new action: Press and hold the space key to jump onto a fence or a block of high obstacle and then jump, you can jump higher and farther.Just like Mirror's Edge Catalyst.
A new action: Swan Dive. Use to quickly through obstacles like the picture, instead of jumping up and crawling through them. I suggest using this combination of keys: W+Shift+Space.

Parkour Gloves: Gloves cannot be held on the offhand.Disable the throw,use,swap item with offhand function from the original game when held in hand.And add exclusive use key(I suggest using f key).In this way, when using gloves, it is possible to avoid using items that should not be used with during parkour.
Falling to the ground animation: Play when the player falls from a high place and fails to use the roll successfully.It takes some time to stand up again as a punishment for the player's mistake.
Custom dodge distance.New optional dodge animation: short jump (just like the old version, it is more suitable for playing game in first person)
Custom speed: Custom fast running speed, various animation playback speeds (although I really want this feature,but I feel it's unlikely to be achieved...).This can make the game easier.
Add Leap Of Faith animation?