Yeah i would agree that having this in IDE as auto-download option is a must.
Personaly i am using Intellij and know that downling app server resources is painles even if you need them even later on when debugging some classes.
but from my quick search around the web i have found that eclipse has this capability as part of m2eclipse integration.
https://docs.sonatype.org/display/M2ECLIPSE/Resolving+artifact+sources
hope this helps in any way.
More help on this subject can be provided by tools guys.
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tomaz