Problem 1: Why would you use the registry to find an app path? What happened to using the system environment path which is already secured? Registry. Pshhh!
Problem 2: Auto Elevation. Microsoft introduces UAC. People get annoyed with it. Microsoft introduces Auto Elevation. Guess what, still annoying and now possible security hole.
I am fine if Windows asks me to enter a user and password to elevate. It works on my *cough* Linux desktop. Annoying? Yes. Secure? More so. But really, how often does one use admin functions?
The way Windows handles stuff I need/user admin features daily. I routinely change my IP address on my interface to work with various systems. I use the task manager to diagnose issues with a system. There are others, but every time I go into the network interface it prompts for the password, I leave the interface for and then go right back into it, I type the password. I understand what the UAC was supposed to accomplish, but in the end it's another layer upon layer of stuff Microsoft has added to attempt to make it more secure.