Have the option for a job to run several instances in parallel.
The use case:
We have a job that gets the branch name as an input and then it builds the project and run the test.
If two or more developers want to build different branches the first one blocks the others. The build and test take a lot of time but with many nodes we can do several in parallel.
There may be a problem with this option if the jobs use the same workspace, but on our setup the workspace is set by time and date with the branch name to prevent this problem.
As this option has potential for destruction it should be under the advance options.