Comfort is the most essential thing when it comes to touring. This is because you will be spending extended periods of time on your bike, so you want to be as comfortable as possible. Thus, your handlebars need to most importantly give you comfort, so that you don't dread getting back on your back every day. Comfort can come from padding, hand positions or the sitting position the handlebars give you.  Each style of handlebar is different and can meet your needs in different ways. So, trail different styles to see which one you find the most comfortable.