Bret is correct about the Rohloff hub and Gates belt. We toured Europe (mostly Italy, Austria and Slovenia) on a couple of Q45s with Rohloff hubs and Gates belts. They were fantastic. The gear ratio we used was determined by the chainstay length and it suited us well. We are slow riders who enjoy the scenery but not the hills, so having a lower gear range than the stock standard worked well. But I'll leave the details to another post. Spoiler alert: it was a bit of pain installing the Rohloffs, but did prove to be a good learning experience.
I'd like to see the carbon fibre front end migrated to the Q45 as the current front end is very heavy.
I'd also like to see more flexible ways of attaching panniers. I rigged up some racks that lifted up our panniers up by a couple of inches as the racks that Cruzbike supply were a bit too low for our panniers. I also rigged up some racks that hung below the seat which allowed us to mount some smaller panniers under the seat. It meant that our centre of gravity was nice and low - ideal for touring. Again, something for another post.