If you read the README https://github.com/memorysafety/sudo-rs

Our current target is to build a drop-in replacement for most basic use cases of sudo. ...

Some parts of the original sudo are explicitly not in scope. Sudo has a large and rich history and some of the features available in the original sudo implementation are largely unused or only available for legacy platforms. In order to determine which features make it we both consider whether the feature is relevant for modern systems, and whether it will receive at very least decent usage. Finally of course a feature should not compromise the safety of the whole program.

So seems like they're on the same wavelength as you are.