Intellisense in AX 2012 was significantly improved (or actually, redesigned). Now it is much closer to the visual studio intellisense.
Suggestions are presented to the user while typing for types (tables, classes, extended data types, etc.), class members and methods, local variables, intrinsic and global functions, keywords. Namespaces and types from the referenced .NET assemblies are also suggested.
Descriptions for methods were also improved. Now they include XML documentation for the methods. That is really helpful.