I'd love to see an enhancement to allow for MIDI keyboard input so I can play along with the sequences. This would be great from both a composition and a performance perspective.
Composing would be aided by being able to quickly test harmonies and melodies that sit well beside and between the randomized notes. I could see this being used to tweak the random sequences more effectively on the fly.
Performances with Cyclic could be a lot more improvisational, I could see having the first two Plugs driving long drones or rhythmic sequences directly from the Cyclic engine and a third Plug with a lead tone used just for a live performance.
I could see the being implemented by putting a dropdown just below each of the Plugins which would let you select the MIDI input device that would control that specific Plugin. All MIDI data sent in from that device would be merged with what is coming from the sequencer. Program changes from the device would be sent to the Cyclic Sequencer, to the Plugin, or both.