The EasyEclipse could come with predefined set of Eclipse Update site URLs. This would go along the goal to eliminate the download hell.
1) One install EasyEclipse Python
2) It does not contain *any* update URLs in Software update menu
3) Google Subclipse
this could be
1) One installs EasyEclipse Python
2) One goes to Help -> Software Update -> Checks "Subclipse"
Since Update site URLs don't add anything to download size you could include update URLs for *all* plug-ins and thus enable single click installation of everything, still keeping download sizes small.