V, when did you climb a C2 route?
Great thread, Michael! I just happen to be working on that fear of falling (when it's safe) right now. Although since I hate the feeling of acceleration, I still would be hard pressed to try your "immersion therapy" suggestion
Although I have been doing something similar.
As soon as this current rain storm lets up, I'm planning on doing a climb that will really push me to my limit, and I know I'd really be better off placing good gear from the starting rest and then "just going for it" through the short crux to the next rest instead of trying to hang out to place gear. Chances of falling are pretty good, but the consequences are trivial and the gear is bomber. I suspect I'll still shrink back to hanging out to place gear, but even risking those shorter falls is new for me.
I've done a few laps leading Sherrie's crack to work myself up to it. In case you don't know it, Sherrie's Crack is a 5.10c finger crack in Yosemite Valley that has a short but fierce crux of intense finger jamming for about 2 body lengths, with lousy feet on a slick slab for the first half, forcing you to yard hard on your finger jams to stay on the rock (it's easy to be doing the Wiley Coyote run with your feet while hanging on your finger jams!). I had considered even attempting to lead it to be a big step, as I'm mostly climbing 5.9 and occasionally (but too rarely!) venturing into 5.10a. I've TR'ed it, so I know it takes good gear and you can jumar the thing on cams if you really wanted to (a follower on one of my lead rounds did this).
I finally worked up the nerve to try leading it 2 weekends ago and . . . it wasn't that bad! I reached high from a stance entering the crux to place a small cam and a nut to back it up (as they were my first pieces off the deck) and while trying to hang on locked off finger jams, I pumped out and fell while trying to place gear, but the gear was bomber and I didn't go far. I've fallen at that crux each of the last 3 leads, but each time I'm closer to pulling through it and each time I place less gear after I've moved through the hardest part of the crux, feeling more comfortable just running with it to the next real rest stance for a placement. Technically on my last lead I grabbed a cam instead of falling, but that allowed me to clip the rope and take a brief rest on the fingers without weighting the rope - a minor infraction as my belayer never even noticed. Not clean, but not as bad as falling or french freeing (as I didn't pull up on the cam or rearrange my stance while pulling on it). It even gives me more confidence trying a harder lead than I normally would try, if the pro is there, since I'm seeing that it really isn't that bad to cheat a little if a fear of falling is all that is keeping you from attempting it - and it's not that hard to cheat a little. I'd say aid climbing has made me more comfortable pulling on good gear if I really don't want to fall
Frankly the crack protects so well that I think it's a perfectly safe lead for someone leading at a far easier level so long as they know how to place trad gear properly. It's funny but after climbing both routes, I think Sherrie's might be a better lead for a beginning 5.8 trad leader to try than Nurdle, which is a 5.8 often climbed to set up a TR on Sherrie's. The first 20' of Nurdle are insecure, with sparse & marginal pro that is tricky to place until the route gets secure, so the leader really could risk a ground fall on it. As long as you're not afraid of falling in and of itself, Sherrie's really is safer and less committing to hurl yourself at rather than climbing Nurdle.
I can see where I need to risk taking more of a whipper at the crux, though. I've learned from some sustained jamming at Indian Creek that perhaps one of the better ways to protect while climbing is to reach ahead and place a cam with one hand, then climb a few moves until the cam is near your waist, and then clip with the other hand. This evens out the hanging & protecting work on each arm, reduces the clipping effort, and reduces how long you need to hang out at any individual stance while placing pro. It's just so hard not trying to get safe and clip that cam once it's right there!
I think another fear climbers should be aware of to work on that is related to falling is a fear of pain. I don't mean the pain of impact, but the pain of truly pushing through the effort required to stay on the rock. When you feel pumped out and ready to fall, it is so easy to grab an off-route hold in the gym, clip in short to a bolt, or try to throw the rope up into your next piece and immediately shout "take!", instead of attempting to move through the pump and pain to a rest (before or beyond a crux) and discover that you might actually not fall. I'm not talking about bad pain (e.g. concentrated pain in the tendons) but learning to recognize the harmless pain and working on that mental toughness to climb until you fall instead of climbing until you let yourself go.
A great book that Dirk (Diggler) gave me that talks about some of this stuff is "The Rock Warrior's Way: Mental Training for Climbers" and I've found it to be pretty good food for thought on working the mental side of leading.