The chance to get a proven probowl QB doesn't come up often at all. Trades of this nature are extremely rare. The Bears have had one glaring hole for years holding them back and thats QB. They made the right choice and will be a better team with Cutler.
That would horrible for Denver.
You don't give up an elite QB for what basically amounts to a late 1st rounder. A 4th round pick and Orton hold little value.