Make a single goal (assembly:assembly) that covers all cases of assembly:attached, directory, ...

It shouldn't be that hard to check wheter it's a multiproject or not.

From a users perspective, when I bind the assembly plugin like this:

<plugin>
<artifactId>maven-assembly-plugin</artifactId>
<executions>
<execution>
<goals>
<goal>assembly</goal>
</goals>
</execution>

it should just work, without having to figure out if it's a multiproject, etc.

Ps: I 've read the 7 different assembly goals 5 times, and I only understand the difference between unpack, attached and assembly...
Great improvements in 2.2's descriptor though