All this stuff is not the same
Well, I did never participate in a wall of death or a circle pit. They usually happen in the first rows of the festival, but I prefer standing in the last ones, so that I am free to move to other stages
Anyway, I don't know wether it is easy or not to escape from a circle pit/wall of death.
On the other hand, you can see people moshing almost everywhere, depending on the concert. Moshing is not always restricted to the first rows. Sometimes I feel like moshing, sometimes not. But if you don't want to mosh, just have to move some steps away, people moshing don't occupy more than few square meters. I think it's relatively easy to scape from it.
And finally we have crowdsurfing. I have never done it, and maybe I would not. I don't have any problem with moderated crowdsurfing. But I dislike it when there are so many people coming to me (or few people but very often) so that I cannot pay attention to the concert, since I have to take care of the people coming to me. I took a long trip to arrive to Wacken, to see concerts, not to watch out the people crowdsurfing to me and who could kick my face if someone else releases the surfer too soon. Moreover, you cannot avoid crowdsurfing so easily: they are coming for you!!!
Therefore I think that all this stuff should not be considered as the same. The injury risks, the localization of the 'risk sources' (circle pits, etc.), the ease of escape and other disturbances are not the same for all of them, so forbidding X (say, walls of death) should not imply forbidding all the others.
In my opinion, none of these things should be forbidden, provided that no one is forced to take part in them. The only restriction would be perhaps to limit crowdsurfing so that one can enjoy the concert without being interrupted every minute by a crowdsurfer.
