Maxfield, you're leaving out some worthwhile info regarding your interpretation of light touring and your weight. Does that mean one set of small panniers or no panniers? If you're very light a modern road bike that can't carry tires larger than 25mm might be acceptable but why bother when there are the mentioned Audax and cyclocross bikes. Nearly all my ultra light riding was done on 80's steel road racing bikes that could run on 28mm tires w/o fenders. Once I had a bike that could carry panniers well I went straight to 32 mm tires for comfort and ease of keeping tires pumped with a frame pump.

Instead of asking yes/no regarding road bikes for touring start with the size of load you're carrying then get the tires and bike for that. I stuck with road bikes because it's what I had and kept the load very small, no tent or kitchen, riding in a region with little rainfall in the summer.