Ok. So here's my thing. Your all asking for sequencer this, sequencer that, etc.. etc ...
But Reason emulate a real hardware studio ... so we should be thinking "what does your average everyday studio have, that Reason doesnt?"
I cant come up with much, but here are my suggestions.
Improved Filter Device - Scream 4's cousin, *Filter 5*
Improved Delay Device - Updated Delay with loads of control over each delay, multiple layers of delays n the like
Improved CV Router - Plug it in on the back. On the front are two simple pull down menus. One for input, one for output. (not sure how this would work, but it would be cool to route stuff to other stuff that doesnt have cv inputs, just to do it via mouse commands!)
New synth based on a famous hardware synth, or really innovative hardware synth: Korg Wavestation in your Reason rack anyone? Access Virus anyone?
Just dreamy suggestions i know, but its nice to keep in touch with childhood fantasies