Im curious. Can you list all the things that are busted? I'd like to know what to look out for.
Nothing that I can see in and of itself. But this is a brand new TouchWiz. That means there are probably thousands of minute changes to the application framework. Inevitably, some of those changes will cause issues with some apps. This is a by-product of Google being loose on rules to use the play store, and Samsung taking the Android Source and customizing it into what they think is the best phone from top to bottom. In the end, it's a good thing and lets us have so many different types of phones that look and feel different when we're using them.
In the short term, it means that Samsung or app developers (or both) might have to make some more adjustments to make everything work together. Since this is a phone that will sell 30,000,000+ units, both parties will spend time and money to sort it out.
Just watch for any major behaviour changes like battery life tanking or real lag (not the Android stutter that every phone has, or a gallery app that can be laggy when you first open it because you've signed into cloud stuff and it's syncing and scanning the media) think about what apps you recently installed or recently used for the first time. Most of the time, this will be the culprit and it's easy to fix.
And please — if you're positive you know of an app that misbehaves on the Note 7, tell everyone here in the forums and file a bug report with the people who published the app. If it's not on their end, they know what to tell Samsung.
EDIT: Since I singled out the gallery app. Having lag when you open the TouchWiz gallery app is normal if you have it hooked into the cloud. This is a good thing (keep reading).
The app doesn't sync with any cloud services or scan the files from anywhere (it needs to be able to build a thumbnail) when it's not active. The process may stay alive, but it sits there and waits for you to bring the main app into the foreground before it does anything. There is no reason the gallery needs to sync in the background when you're not looking at it.
When you open it, the bigger your cloud-based gallery is and the slower your connection speed is, the more chance it has to lag. Alex and I made a dropbox folder with a gazillion or so pictures in it and could bring the S6 to its knees for like 5 minutes on a bad Sprint connection.
Every tiny bit of battery and data saved counts!