As my team started looking at these existing applications, they came across a lot of "technical debt." The applications were developed and enhanced by a number of different developers with different skill levels (some with low skill levels for working our our products). So we have a lot of code that's going to be hard to maintain and enhance.
It's a tough situation. The client uses a charge-back system to charge the business units for development, so we don't have money to just go in and completely re-factor an application, even if it needs it badly. On the flip side, both new enhancements and maintenance take longer because of the debt we've inherited.
For now we're going to have to live with it. We'll try to pay off the debt slowly by cleaning up parts of the code as we do our development or maintenance. I think the client is starting to realize the cheap solution for development wasn't necessarily the best.