This has been discussed many times, see also: https://strategy.wikimedia.org/wiki/Proposal:Multi-level_Articles_(By_Diffic...) https://strategy.wikimedia.org/wiki/Proposal:Filter_content_based_on_desired... https://strategy.wikimedia.org/wiki/Proposal:Divide_Wikipedia https://strategy.wikimedia.org/wiki/Proposal:Create_Scientific,_Popular_and_... (and links from there)
Federico