I'd like to suggest making the nullability of the generated properties optional. I think for most use-cases it can be safely assumed the resources will always return a value (falling back to the neutral language if the thread's current language is not available).

As it is currently, I'd need to litter my code with lot's of ! everywhere I access Resources (e.g. string.Format(Resources.MyResource!, someVar) instead of string.Format(Resources.MyResource, someVar).