I think instancing in maya needs to be looked at again. Here are a few suggestions:
-make an instance recognisable in outliner
-make an instance a container for multiple object (like xsi's 'model')
-make it procedural so you can drag and drop items into the model so it gets updated in all the instances
-option to turn an instance back into normal geometry
- easily editable in the node editor
- completely stable and reliable