|Shoulders have got too big|
If you're plonking about on english 6b/6c moves, then you don't really need to worry about this. Perhaps you'd have to lift your leg a bit to do the odd move, or even gaston if you're really feeling expressive. A recent thing up at thorgill though needs you to come onto an undercut with a couple of fingers and then spin round on your shoulder. Last year I probably wouldn't have been able to get to the undercut, but I would have had no problem twisting my shoulder out of its socket to match the hold.
When I tried it this week though I just couldn't do it. Too many fibers, too many tendons, just too ripped. O dear... So now I'm training. I've got a wooden broom and am trying to do those weird twisting things that dislocate your shoulder. I'm pretty psyched for this route.