"I Think We've Just Stumbled Upon a Larger Plot"

You know, heroes aren't just puppets to be ordered around by an army of contacts (who seem to be the only ones who know what's going on in Paragon City). Heroes can discover the nefarious plots of evil-doers too! We're not just tool, after all. There should be a system in place to allow heroes to find their own paths (and gather that XP bonus) without needing the say-so of a contact. I've combined this thought with my ongoing desire to make random street hunting more interesting. There's a couple ways I can think of to do this:

1: At random. While hunting (these kinds of "missions" would only be discovered through defeating non-mission villians), the hero discovers a "clue" of some larger, unsuspected plot. I like this option, but I've always like the occasional random special encounter.
2: After defeating enough villians of a given type (Hellions, Freaks, etc.) a hero gets a "clue" that something is afoot. This can be kept track of by the game in the same way that "defeat X baddies of a given type"-badges are. Perhaps at about 3/4 full bar of such a given badge, the hero discovers the clue.

At the time of discovery, the hero can choose to either follow the clue (ie, accept the mission) or "pass it on" to an existing contact to to be followed up on later. The mission would be listed the next time the hero checks in with the contact.

This idea also falls into the concept I'm developing for hero "skills" (which I'll expound upon shortly). This could be part of a "detective" skill.