Surely it is too early to be throwing toys out of prams about the challenges!
Yes, I can see that people don't like change, and yes I can see that (at first) there may be a lot of silliness around the challenges that people set. But this is something new and it will take time to build. Groundspeak have tried to come back with something for people who bemoaned the loss of virtuals, webcams etc.
I haven't quite got my head around the physical challenges yet, but the photographic ones have a lot of potential.
You will be able to set challenges that take people to areas that you want to show them, where you can't place a physical container (surely just like virtuals) and the proof is shown in a photograph.
Even Earthcaches ask for photographic evidence, how often do we see the line "to claim this cache email a photograph of you holding your GPS at ........location" Photographic challenges can be set in a similar way if you set one in the right place.
Obviously with an Earthcache you are hoping that the person will learn something about the area you send them to. Can the same not be said for the photographic challenges?
Webcam caches quite often asked you to do or wear something different to prove that it was actually you, so I don't see much difference there either.
As I said at the beginning, there will be a lot of silly challenges set at first, people will try to stretch boundaries, but come on, as with anything new, it will take time to settle down and be tweaked. You just have to look at Munzee to see that happening and how it is already developing.
As with anything in life, isn't it better to suck it and see before making a decision.
I myself like the old adage. "If you don't like it, don't do it" But please don't write it off just yet.