What does it take to have a revealing system?

Get a decent pair of headphones and a suitable amp.

There is no more practical way to reveal what is in the music.

Lwhite's list is pretty good but also demonstrates how much work can be involved.

REgarding what or how much it takes to accomplish a revealing system, starting with headphones as a baseline simplifies things considerably.

Then you can focus on teh remaining room acoustics related things needed for speakers from there using the headphones as a reference for what to expect to be able to hear.

I'm a big fan of OHm Walsh speakers as a great starting point for many in terms of being able to well integrate speakers effectively into typical listener's rooms at home in a manner that is cost effective yet revealing and will tend to naturally draw you into the music and details repeatedly when you listen.

1) Good setup.
2) Well matched gear (doesn't have to cost a fortune for most rooms)
3) low distortion.