Today in SSIS we build, distribute and execute these things called packages. Packages are fairly large, verbose, non-descript BLOBs and that has some rather negative implications such as:
-Changing anything in the package, even something as small as moving a container one pixel to the left, causes the package to get checked out (assuming you have your packages under source code control)
-Support for multiple-developer teams is limited. If you have two people building dataflows then they have to be working on separate packages.
-The only method of reusing tasks is copy-and-paste
-Comparing two packages to check for differences and hence merging them together is not possible