I have been thinking about getting/builiding one bike to do it all as well, but so far no luck. Do it all does included cyclocross for me too though, which doesn't appear to be on your list. In that case do it all is doable. The Rouleur appears to be a nice smooth tourer bike and it ticks all the boxes, but the best I can see the frame does not have any fender or rack mounts. For me a commuter bike needs to have these, seeing as non bolt on fenders kind a suck and carrying around stuff on a rack beats having to carry it on your back every day.
Sine my commute is mainly on a nice paved path, I have realized that the 28mm tires i run are not a necessity. I can run 23mm tires on the new bike with the pdw full metal fenders which are not flimsy - I actually see a lot of people here in Portland running this setup. I always use a messenger bag as I am not a fan of the panniers or a rack.
Having multiple bikes is always the best way to go. I have my road, CX, fixie, tt and mountain bikes as choices for the day.
I'm not familiar with that model but I have had my R320 six years this month. The honeymoon is not over and I plan to still be on it 6 years from now. I did previously change up bikes every few years but my Lynskey changed that. It just feels great every time I ride it.
I agree having multiple is key, I do have multiple mountain bikes. Its been really tricky with my road bike though. I have had many a nice road bikes that sit since they only get ridden during the weekends on summer months here in portland. I always enjoy the weekends rides but the majority of my summer mileage is done during the week, after work I go out for long rides. So ideally would be great to have a good middle ground bike I can commute on and also do my longer rides on