The amount of time it takes to perform upgrades.
Multiple systems, multiple modules, multiple pollers, multiple upgrades per year (not that I don't like the upgraded function!) become very time consuming.
Perhaps development could think of a way for all the modules to be packaged in a single certified install package - with the modules enabled via the licences installed.
It would be nice to have a regular upgrade cycle where I don't have to worry about module compatibility, and performing multiple time consuming upgrades.
Dave.