What kind of touring are you thinking of doing? A compact double could be fine for ultralight touring, credit card touring, etc., or if you're young and a strong rider.

I have a compact double on my road bike, and it's fine for that. But I'd never run that on my touring bike. I don't ride light, and I'm not young. Loaded, the touring bike weighs about four and a half times more than the road bike and climbing hills is hard enough already. Even with a 36T cassette I could only get the gear inches down to about 24 with the compact double (50/34) and then would have to deal with big jumps between gears. Smallest chainring on the touring bike is 24T and even with just a 28T cassette it gets me down to 22 gear inches and gives me a lot more choices in the middle. To each his own, but for myself a triple works best for loaded touring.