I was looking to some examples of the use of 人 and I found this one in Jisho.org
２００人{にん}の人{ひと}が昨年コレラで死んだ。
Two hundred people died of cholera last year.
With furigana for the first case にん and for the second ひと. So I was trying to guess why is the kanji repeated and I thought that probably it was due to the need to indicate what were you counting. But then, wasn't supposed that ～ニン implies that you are counting people?
Yes, 人【にん】 is a counter "agrees" with person, but no, it cannot play the role of a noun. Counters only makes a number able to modify a noun, but grammar prohibits it from having noun meaning. Thus, if you want to tell "two hundred people" you always have to say 200人【にん】の人【ひと】. It however doesn't mean the noun is not omissible.
村には500人の人が住んでいたが、200人が昨年コレラで死んだ。
There had been five hundred people in the village, but two hundred died of cholera last year.
This basically explains the nuance of using counter phrase alone.
PS
Analogy in English...
(??) I'd like to live a happy one.
I'd like to live a happy life.
If I could choose how my life would be, I'd like to live a happy one.
Think of it this way: the noun 人{ひと} could be replaced with another noun, which may or may not have 人 in it.
Examples:
米国の大使館の前に100人のアメリカ人が集まってきた。
今年のコンファレンスに1万人の技術者が来た。
ファン50人が乗ったバスが出発しました。
