"Extra space above" parameter for system brackets
Typically, ensemble scores larger than about 6 staves will be divided into sections (such as woodwinds, brass, percussion and strings) separated by extra-wide inter-staff spaces. Currently there are two methods I know of to create this space:
With the "extra space above" parameter of staves. This has the downside that the space goes away on each page where that staff is hidden. E.g. for an orchestra, if the timpani are hidden in a system, the space between the percussion and brass sections will go away.
By adding staff spacers on each and every page of the score. This just takes a while in large scores. They can't be copied and pasted, so you have to type the height value for every single one.
Most of the time, method #1 will take care of 50%+ of the desired spaces, and method #2 must be used to fill the gaps.
I suggest allowing system brackets/braces to have an "extra space above" parameter, which applies as long as the bracket or brace is visible. That way, the space to the next staff above the bracket will be maintained, regardless which staff within it happens to be on top in a given system.