> That said, I really wish there was a "I know what I'm doing" checkbox to avoid a lot of that BS...

The "I know what I'm doing" approach is the absence of the checkbox. Each of these decisions matters, and gives you insight into what the programs you're installing are trying to do today, independent of what they did when you last installed them (and maybe audited them) five years ago. Neither default behavior of "disallow all" (which would prevent correct operation of many programs) or "allow all" (which would likely violate your trust assumptions) is safe -- thought and human decision-making based on your own risk model and your own intended use of the installed software is needed.