[FreeFull]

I'd say having special features is ok, as long as these criteria are met:

1) It's obvious the feature is being used.

2) The feature is easy to look up without knowing what it's called, just based on how it's been used.

3) It's easy to understand what the feature actually does, with the appropriate context.

[estebank]

The ? operator doesn't fulfill at least two of the three points, yet it's way more loved than hated. As a general guideline I agree with your points, but it is not to be taken as rigid gospel either.