Programmer's Notepad will never be an IDE - it's a text editor and has different strengths. While we can make progress towards better intellisense-like features, the level of effort that goes into per-language support for something like Visual Studio/NetBeans is simply impossible to match on a small project like this. It's also fair to say that this kind of code completion and intellisense is one of the reasons these IDEs are so heavyweight, which is where you use PN.
I use PN for lots of things personally, but I develop PN using Visual Studio - I'll let you draw your own conclusions!