Honestly this is so disappointing.
Highlights & Shadows is the only really interesting tool in Aperture. It permits a lot of control in a complex way. It is pretty hard to imitate this tool in other ways and yes, it is also hard to use, but why have Apple simply chopped it out? The replacement version is next to pointless and is easily replicated with other tools.
To me this simply smacks of Aperture being geared more and more to amateurs and less and less to professionals.
(For those that want to keep using it … make a preset with it (from an existing image that uses it) and apply that preset to your images. NB … this is definitely a temporary measure. I know Apple and it'll be completely removed in a future version).