When modifying an existing workout to adjust the difficulty it would be good to have a percentage increase or decrease slider for a block of efforts within the workout. warm up and recovery typically remain the same.

this would help build athletes as they get used to a specific type of workout

example: a sprint session for cyclists with a sprint target of 200% FTP with the new percentage increase option for the block you could simply add a 15% increase and it will amend the block accordingly - this would help in a multi step block rather than adjusting each bit individually.