1. uniform function names and parameter orders. for example searching functions.
2. better way to define stdClass objects (json-esque). other than (object)array('foo'=>'bar').
3. chaniable interfaces for lots of stuff that currently requires storing results in temp vars.
4. have closures automatically "use" all local scope variables without needing to explicitly define them (like js) - this could be problematic though if you expect to reuse variable names...
have anything implementing all necessary array and iterator interfaces be passable to functions that take arrays. this is really a core language feature though, not sugar.
there is a great list of warts you can start itching here: http://phpsadness.com/