Cura is really nice for it's simplicity, nice visualisation and manipulation of the object. Unfortunately because it's support feature are so much better than slicr3 I tend to use it more and jump between Cura and Slicr3 slicing engine. The easiest is to use MatterControl who offer all the nice user interface control and the ability to use slicr3 or cura slicing engine.\ 3d printing service surat delhi pune india
But for Cura software a few features are missing the most important I think are in no specific order
Ability to change bridge settings forcing you to use support more often than needed.
Ability to customize speed settings for various part of the object
Variable layer height feature from slicr3
Ability to set different temperature between first layer and the rest of the object, Simplify3D as that really cool feature (called setpoint) where you can define temperature of hotend or heatbed for a range of layer e.g when I print with a raft I usually switch off the bed after the raft has been laid out and the first 5 layer of the object is printed or you can use it in many other different way.
Ability to change infill pattern and orientation of infill pattern
Ability to perform a cut of an object into 2 parts this is more often than we think the best solution to print really toough object
Ability to save as an STL actually most slicer also miss that feature except MakerWare and MatterControl
I think that's all for me I must miss some things that annoy me, but some of the missing features are available when using MatterControl but still some of the them listed above would be nice to get in the Cura software.