OK, this was covered almost a year ago, so let's review;
You should be able to select any number of clips and adjust any parameter globally amongst them. For example, you are working on a piece of music and at some point you decide to change the key. As Live works now, you must select and transpose each musical clip one at a time (often dozens of clips - sometimes hundreds?). A global editing mode could allow you to change the value of one clip's transposition knob and others would follow.
Likewise, I've often found myself adjusting clip's "groove" parameters to experiment with different feels. This would be much easier if I could adjust multiple clips in my song simultaneously.
feel free to tell me that I'm brain dead and this feature already exists (but at least tell me how)
!P!