Just what purpose do these useless characters serve? (OK, maybe a source for better armor!) But why the ____ don't they tell you WHERE the trouble was happening? Seems like they are toss-in NPCs and could have been so much more.

Mercenaries are supposed to help you on your journey. If you find the game is too easy and they're doing nothing, up the difficulty. If you're playing on the PC, try a mod like Unleveled Skyrim.

I usually get a mercenary to be my house carl; This involves furnishing my house, keeping it safe, and hiring talent to play for me. The last time I brought a mercenary with me, they died and I felt guilty. So I travel alone now.

The random, nameless Mercenaries will add a marker to your map, assuming you haven't gotten it already, but they won't tell you which one it was, so if you have some already, ti is impossible to tell which one they were headed to.

Strikes me as strange that you can't hire them, or team up with them for the sake of taking out that one cavern they are headed to.