I want to second Tim's well-considered list of recommendations for PSP. They would improve the program tremendously and go a long way toward boosting Corel's reputation with PaintShop Photo Pro since acquiring the program from Jasc.
As a PSP user from the very early days, I like the addition of the automation tools that make it easier for newcomers and longtime users alike to perform some operations. That's one of the reasons I use scripts often -- to save time. The new market is DSLR users, and the competition is providing the automation tools, like panorama, for example. Corel's mistake here was to strip muscle from some of the basic tools that Tim mentions.
On the work area color issue, perhaps the better approach would be to provide an adjustment slider, allowing the individual user to choose from a light to dark setting. That's how Photoshop Elements does it.
On adjustment layers -- PhotoLine has 34 different function layers, PSP 9. Corel is far behind on this one.
I would add one item to Tim's list -- Add additional adjustment options to the Object Remover tool to improve its function.
Aftershot Pro; DxO Optics Pro 7; ACDSee Pro 6; PSPX5 Ultimate; Sagelight 4.3; Xara Designer Pro 7; Olympus OM-D E-M5 m4/3 camera