After i joined this site, it took me about a year to start posting thing on it, partially because i didn't have much to say, but also because i was afraid not to have good enough/ interesting enough things to share.
When i felt i could maybe be of interest, i wrote something. I am not saying everyone needs to wait all that time, but one fear i have is that opening to wiki would make some people just start posting away without giving much thought to it, albeit with a good heart.
One point some wiki sustainers bring is that most pages would be collaboratively written by not more than a few contributors, since the quantity of contribution has gone down, and many just post photos, so there should be no fear of edit battles, but that is how things would work applied to the current population of SP.
I have a feeling that would change, and soon there would be edit wars.
Still, don't take me for a bigot, i can understand the points in favor of the wiki approach, and i find them strong and valid. I simply think it's positive aspects can be obtained by tweaking the current system, without the potential drawbacks.
I like the idea of the open appendix section with proposed edits remaining visible until integrated or rejected, and i think it would be a great starting point to test all of our hopes and fears. There is no need to make it secondary and half-hidden. Make it visible and important, it will be like writing margin notes on an older guide. (With the difference these notes can be integrated).
As i see most people would be ok with that, why not decide to try it now? or, say, decide by page 16 of this discussion.
Another interesting point someone made (sorry, the discussion is getting long and i don't remember who it was), was the possibility to use the collaborative option to write pages about routes or mountains for which one has the knowledge but lack the photos, or vice-versa.
There might be a way to help people in this situation without the wiki approach.
Why not open a section of the website for "pages in progress"? It could be made visible on the site, so that people would keep being reminded of all the incomplete pages there are and these pages could benefit from contributions from other members, coordinated by the page opener. All contributors could receive credit for the page, while ownership, once the page is closed would be of the main contributor (Not necessarily the page opener).
I think this "Lab" could give some users the creativity, dynamicity and collaborative spirit they are looking for, while maintaining all the features of SP we all know and enjoy.