Reason 2.5 is out today! Advanced Reverb, Vocoder, Scream 4 Sound Destruction Unit, Unison and splitters & mergers for audio and CV.
I'm looking forward to playing around with the new additions, but the main thing I'd love to see would be for them to open up the whole annoying proprietary Refill format. That would actually increase its usefulness as a product and strip out a whole level of stupidity users have to cope with. I know that will never happen, but it would be nice.