This. I think it's a neat idea though! Also, you'd always get idiots that would walk towards Slender actors and follow them. And because unlike a maze, the woods isn't a controlled environment and many guests might not see the incentive to move on through the attraction.
As with the torches, many people might throw them if they are scared, or even use them as a weapon if the actor takes them by surprise. It may sound stupid but it can easily happen!
One last thing, I don't really think many people would find it scary? Especially as they are in a group with friends. I could only see people being genuinely terrified if they were alone, but then the throughput would be so awful there would be no point in running the maze in the first place.
I think it's actually a really good idea though! I thought the camp site and the bridge were neat ideas, but I think it needs some tweaking here and there!