I would like to see the AspectJ language added to the Java language. It does not break anything, so nobody would be forced to use it or change any line of their code if aspects were added to Java.
AspectJ increases the expression power a lot with a small number of additional language constructs. It is just so ... neat.
I would like to be able to use join points in normal Java classes, not only in aspects.
I would like to use any Java compiler instead of being refined to the AspectJ compiler. E.g. for now it is not possible to use AspectJ together with J2ME. (Or is it, and I just could not figure out how to do it?)