The ForEach loop is a very very useful tool for SSIS developers but it does have the advantage that it works serially i.e. Each iteration of the ForEach executes one after the other.
In the future multicore processors will be ubiquitous so would it not make sense to give us the ability to execute some of those iterations concurrently?
Here's a use case where this would be useful:
We are looping over a list of computers from which we need to fetch some files via FTP. Why can we not hit each of those remote computers at the same time? There is no reason why not yet the ForEach Loop in SSIS2008 prevents us from doing so.