Maxperson
Morkus from Orkus
To my mind, the distinctions being drawn here have nothing to do with realism. They are about preferred stakes for certain game checks.
In the real world, a skilled climber is:
* Less likely to drop/lose things (better packing, more careful in avoiding snags, etc);
* Less likely to have handholds break under his/her weight (better judgment, better/more careful testing of holds, etc);
* Less likely to get frostbite (better at wearing protective gear, better at judging when fingers are getting too cold, etc).\;
* Etc
Of course suffering any of these things is bad luck, but skilled climbers make their own luck. Putting it all into a non-skill-dependent "fate roll" or skill fumble system does not seem, to me at least, to encourage or reflect realism about skill with climbing.
What it does do is confine the stakes of a climbing check to one very narrow question: does the character go up or down? Personally I don't think that's the only interesting question (or, always or even often, the most interesting question) to ask about a fiction in which a character is trying to achieve his/her goal by climbing up a mountain.
I'm not 100% sure what "connectedness" means here, but if it's a reiteration of "realism" then it's out of place as far as the ascent of Mt Pudding is concerned. There is no more or less "connection" between climbing skill and not falling, climbing skill and not having a handhold break, climbing skill and not dropping or snagging some gear, climbing skill and not suffering frostbite. All these things are connected to how skilled one is as a climber.
Examples of "non-connection" have been given upthread - eg there's no connection between skill in Scavenging and a PC's brother having been evil even before possession by a balrog - but Maxperson's complaints aren't directed at those examples.
"Holding tight to the story" is a red herring. In [MENTION=6696971]Manbearcat[/MENTION]'s example, no one is holding tight to a story. The question is about what can be at stake when a check is declared and resolved. One might even say that insisting it must always and only be one thing - does the character go up or go down - is a form of holding tight to the story!
As I've posted repeatedly upthread, the "problem" for which "fail forward" is a fix is that of achieving a dramatic story via RPGing without the GM preauthoring a story.
If you don't have that problem - either because dramatic story isn't a high priority for you in RPGing or because you don't mind GM pre-authorship (and historically, D&D play has tended to fall into one or the other of these camps) - then you probably won't be interested in "fail forward" as a technique.
But this has nothing to do with what is or isn't "realistic" as stakes for a Climbing check.
It is all about realism. There is climb skill. The skill with climbing. And then there is experience with the event in general, which would include pack preparation and cold weather gear to prevent frostbite. Experienced climbers will be prepared. Their skill in climbing, however, doesn't come into play until they are actually climbing. A failed climb check determines that they fall or fail to climb farther along. A broken handhold could be a reason that they fall or fail to climb further. Picking the route is a part of the climb, so that example is not of something unrelated to the climb skill.