My music is rather glitchy and I like to include some random elements in the mix from time to time... The following features would make Live so much more appealing to me ::
1. A system where rules could be applied to a sample to trigger it randomly. Rules could include its quantization, density [how often it is triggered], randomization of it's other parameters [volume, panning, pitch, etc.]
2. The sending of midi clock to the VST effects would be great, also. I like to produce my own effects using Max/MSP/Pluggo, and some of my plugins add random audio to the stream, but they require the midi clock or midi sync to be available to them.
3. Multiple output device support to allow monitoring via the built-in sound device, leaving all channels of an ASIO device free.
4. Seperate quantization settings for each track/sample/row/etc.
5. Some strange triggering effects, like the peaks of a drum loop cause another sample to be triggered.
6. Make Live write my music for me!