Is there an alternative to delegated properties for observing changes to all properties on a class? Even a hacky reflection-driven way would be fine... Right now, I'm having to add the delegate to every single property and it's easy to miss one (especially in subclasses)

You can write a custom generic delegate (plus for primitive types if you have to avoid autoboxing overhead) that takes as a parameter something that will notify observers, and use this delegate for all of your properties. Unfortunately, there's no way to enforce it on subclasses other than documentation

Thanks for the suggestion. I ended up going in a similar direction, and although it’s not ideal to be able to accidentally forget to add the delegate to a property, it’s working pretty well.