Smalltalk is exactly like that - other objects' state is only mutable through explicit message passing. It's also widely considered the penultimate pure OO language.
> Pretty much all of the OO languages are walking back OO features
About the only feature I can think of for which this is somewhat true is inheritance, and that's because we realized that aggregation is often a better model, and can be easily supported by the language to be no more verbose. But it doesn't fundamentally change OO - it was never about inheritance first and foremost; I mean, prototype-based OO doesn't even have that conceptually.
> and trying to add type classes (contracts)
In most OO languages, these typically naturally evolve out of interfaces.
> functional pieces, mapping and filtering a la linear data transformations.
This is not contradictory to OO in any way. Again, Smalltalk has had "select" (filter) and "collect" (map) from the get go.
