Short answer
Yes, it would be very unwise.
Long answer
"I feel that I am properly protected without it". What do you base these feelings on? Do you base it on research that you have done that indicates that your software solutions are just as good at protecting your machine from attacks without NAT protection as they are with it? Do you base it on a full understanding of how attacks are made, how they can be guarded against, and the differences between hardware and software solutions against these attacks?
My words may be harsh, but my point is valid. Unless you are a security software and hardware expert, you have little idea of how complex attacks can be and how vulnerable your machine truely is without layers of comprehensive security. How do I know this? I'm an IT professional. I maintain a number of web servers, and I see how our boxes get attacked all day long. The more I have learned about how attacks work and how they exploit weaknesses in security, the more I realize that I know very little about the intricacies of designing and maintaining software and hardware that will offer the most protectection possible against all foreseeable attacks.
The way I think about it, there are four main lines of defense in computer security.
The first line of defense is your hardware. Think of the hardware security as being an armored fortress. It may not protect you from …