An option to allow an addon's content (classes + resources) to be visible for all other addons is needed.

Some frameworks are not prepared for modularized environment, and working with them then is a hell. For example, logging frameworks, which initialize pretty much randomly, under undefined conditions through unknown classloaders, hence, adding a logging addon to specific addons doesn't help - one needs to add it to all modules. Which kind of defeats the purpose of modularity.

Having this option would save a lot of depdendency maintainance effort.