Can I ask if anyone has been in a company who has replaced over 5 million lines of cobol with Java and how was the project managed.
There was a lot of pressure to get something done "now", which contributed a lot to the problems that were faced. Hindsight being 20/20, if you want to go down the path of refreshing your systems a better approach is to take the time to define exactly what the systems do (factoring in not only the original design but also however many years of minor enhancements you are dealing with), identifying the gaps between what they did and what you want them to do, and coming up with a comprehensive list of requirements for all components of the program before starting any development work.
Apparently this cannot be done without significant cost.
That was pretty much our experience. But if you don't spend the $$ and time to do it right you will pay more in the long run from not only a systems re-work perspective but also from an employee satisfaction, customer satisfaction and reputation perspective.