And I want to add a link to a section the_section_1 on the same page, I must use this kind of link :
[[#the_section_1]][/m], or better, [m][[#The Section 1]] as it corresponds with the section title.
It would be nice to be able to use a keyword like this ThisPage
I'm pretty sure we have this. Check the interwiki and link syntax pages.
t would be nice to be able to add a new page on the same namespace by simply adding a link like this [[My New Page]] or [[.My New Page]] (for each point '.' up to one level in namespace ?)
[[.page_in_the_same_namespace]][/m], and navigating namespaces up is done the same style as UNIX paths: [m][[.:..:..:page_in_grandfather_namespace]].