Java driver 3.x has many codecs in the extras module. Most of these do not have any equivalent for driver 4.x.
Add support for:
LocalDateTimeCodec (could take the ZoneId as a parameter instead of hard-coded UTC)
ZonedDateTimeCodec (storing a tuple, which is different from the current one)
Most of the above codecs could be added directly to driver-core, as all the dependencies required, including Jackson, are already present.
However the codecs for Joda Time and other Json libraries would require additional dependencies, we may chose to not include them for now.
For Json, if we could come up with an abstract parent class that is agnostic of the actual Json library, that would at least allow users to create their own Json codecs very easily.