For example of already-thought-of important ideas, William Godwin is very neglected. In part due to sexual scandal -- basically just sex outside marriage which was a lot worse then (1800ish). In part due to honest memoirs about his dead wife Mary Wollstonecraft (the first feminist). Partly due to the getting lumped in with French Revolution supporters. But in the long run, mostly because his ideas are not popular.

Of the few people who've heard of him, most only care because they like the history of England or anarchist political philosophy (he's sometimes called the first anarchist, but I don't think that's true). Most neglect one of his top 2 books:

The Enquirer: Reflections on Education, Manners, and Literature

(His other best book is called Political Justice, and the subject matter is the reason that it's better known.)

BTW, his books are out of copyright, so you can legally download them for free. See here: http://curi.us/main/godwin_download

Here's a quote:

Let us consider the effect that coercion produces upon the mind of him against whom it is employed. It cannot begin with convincing; it is no argument. It begins with producing the sensation of pain, and the sentiment of distaste. It begins with violently alienating the mind from the truth with which we wish it to be impressed. It includes in it a tacit confession of imbecility. If he who employs coercion against me could mould me to his purposes by argument, no doubt he would. He pretends to punish me because his argument is strong; but he really punishes me because his argument is weak.

Consider the consequences of this insight not only for spanking children, but also for ordering them about or punishing them. Restrict your reflections to children over age 6 if you want, just to make the situation more clear.

There's lots more where that came from.