I would love to see the ability to "disconnect" the rhythm and melody components much like the way early apreggiators running off old drum machine external clocks do. This produces some amazingly complex melodies from very simple variations.
Since this sequencer behaves very much like an old analogue step sequencer, it would be entirely in character!
Basically I suggest some combination of buttons would allow you to set the "melody length" as seperate from the sequence length. ie: if the melody length is 4, the notes in the first 4 encoders are cycled through in order (forward, reverse or ping pong as per setting) as the rhythm sequence is played through. The note setting on the dials would not directly correspond to the buttons below. Even better, if you could set the rhythm and note sequence direction seperately, this would give even more complex variations from simple changes...
Together with a simple means of "syncing" melody and rhythm loops with the internal clock, these changes would make this little sequencer a must have for me.
For now, I will have to just keep playing with my 606 and 101...