For one thing, the op mentioned that, while functions should be small, they usually aren't.

Functions shouldn't be small just to be small. Functions should be exactly the size needed to encapsulate their function. I had to wade through a few thousand lines of JavaScript in which every function was made as small as possible (since functions are supposed to be small). Stuff like (and I am not exaggerating):

  var xor_it = function(a,b) {
    return a^b;
  };

  var xor_them = function(l) {
    out = 0;
    for (x in l) {
      out = xor_it(l[x], out);
    }
    return out;
  };

Turns out that, when functions are written based on small size alone, it is nearly impossible to build a mental model of a system. I've reverse engineered some ugly code (the previous worst was an object oriented system hand-built in C (with constructors, vtables, and all)). That was child's play next to a few thousand lines of three-line functions.

On topic, I tend to agree with you. The best parts of Light Table have existed in one form or another for years, but that doesn't mean it isn't worthwhile to "Try, try again". Approaching an old problem with new vigor can result in amazing things, or nothing, but if you aren't willing to listen to criticism, you will never make a better mousetrap.