It is difficult for the GM, that's for sure. I was never competitive, so I didn't mind just loosing for the sake of story or wasn't invested in my character performing well - quite the contrary, I've always enjoyed underpowered RP characters more than all-powerful warriors, and just having one D10 to worry about introduced just enough randomness for it to still be interressting with critical misses, while also letting the GM to give us an experience that would be fun and enjoyable, because there are no rules that would say "you can't do this". And from my experience GMing one such game (on the same summer camp, once I was older), it's surprisingly intuitive experience - I never really had to think about "Ok, how much for this skill check?", but always just let them describe the action, roll, and then have a pretty clear gut feeling on whether it was enough or not. I was pretty nervous during that game, since it was one of my first time GMing and for people I didn't know, and without a rule system to hide my decisions behind, but it just worked well and everyone enjoyed it.

But you are right, I now much more prefer some rules-light systems that give you and the GM at least some base to go on. Or Dread. Dread is the best system I've ever used, and to this day is one of my most favorite examples of unique and really clever game design.