Idena verifies that a person is participating, and it makes the 'work' of each of those people financially equal, but the thing that stands out is that the 'work' is non productive, as with bitcoin.

You can verify that a person is 'mining' be either having them do productive or unproductive work.

At some point people will develop scripts or bots to do whatever a 'human centric' coin will do.

And it is better to have those hackers or bot makers develop scripts to imitate productive work rather than unproductive.

If you found a way to have idena miners verify their presence by doing some human work along the lines of primecoin or gridcoin you would become the number one coin, maybe ahead of bitcoin, until you got copied and cloned to second place.