If I was designing a cyclocross bike, I design it with lightweight tubing (particularly across the top of the frame diamond, which is very lightly loaded) and components since part of cyclocross is picking the bike up and carrying it. The wheelbase/chainstays would be relatively short. It would have a relatively narrow range of gears, since cranking out high speeds is not required on the local cyclocross courses. It would have a high bottom bracket for clearance over obstacles, and the gears would be achieved with relatively small chainrings and a relatively short derailleur cage. I wouldn't care so much about saddle comfort, and I wouldn't need saddle bag loops or fender or rack braze-ons. I'd accept higher maintenance as a trade off for lighter weight (thinking especially of the wheel here), since the bike would seldom be ridden for more than 2 hours without being taken home where it could be inspected/prep'ed. I'd fit light nobby/aggressive tread tires.

If I was designing a touring bike, I'd design it with heavy tubing (particularly across the top of the frame diamond) to resist frame twisting from the pannier/rack loads on both ends of the frame. The wheelbase/chainstays would be relatively long. The frame would have a full complement of braze-ons for fenders, racks, multiple bottles, lights, brakes and pump. The components would be chosen for robustness and minimal maintenance needs. I would want very wide range gearing. I'd want a relatively low bottom bracket for a variety of reasons, but that's personal preference. The saddle would have to be supremely comfortable, and I'd want the wheels to be able to go 1000s of (your national distance measurement here) without giving trouble. I'd fit smooth rolling, supple riding tires.