"developing" is not a noun. It's the form of a verb called the gerund, and it has a dual nature, -one of a verb and one of a substantive.
Its verbal nature is shown by
a) its ability to take a direct and an indirect object.
b) the fact that it can have a subject (I was proud of him being my son)
c) is ability to appear in different tenses (he boasted of his having killed her)
Its substantival nature is shown by
a) its ability to be the object of a preposition (by doing so)
b) the fact that it can take a plural ending (such going-ons)
c) it can take an attributive adjective (his dangerous driving)
d) its ability to take a definite or an indefinite article (a hanging was once a public amusement)
The active form of a gerund is often used in a passive sense (your hair wants cutting, the garden needs weeding)
In parallel cases a noun ending in e.g. -ment would normally imply the result of an action,
the product of an action while the corresponding gerund would refer to the action itself.
Take for instance "extension" vs. "extent" or "export" vs. "exportation.
A gerund would normally have in it the verbal nature which the corresponding noun need/does not have. Compare "The king's arrival was met with much enthusiasm" vs. "We are quite tired of his usual arriving very late".
In the case of "developing" one might compare "The development of AIDS in Africa has proved to be one of the biggest tragedies in the Third World" vs "The new president aims at developing the country's poor-relief system".