I have to agree with the other guy on this one. Sloping top tube bikes are terrible. A bit of slope is ok, and is actually necessary on the smaller frame sizes, but the trend has been getting ridiculous lately.
The stiffness argument isn't a big deal for tourists who are not focused on performance. The main problem for me is that a loaded bike is extremely heavy and when I'm stopped I need to use my legs to control the bike's top tube. On a sloping top tube frame the top tube is too low and the bike flops all over the place. I also cannot rest by sitting on the top tube.
Also it looks ugly. Looks matter. Maybe I'm superficial but I don't want my expensive touring bike to look like a BMX.
Gord, the other poster, complained that a sloping top tube of more than 2" is ugly and limits use.
A 2.5" sloping top tube on my bike would be a 5.8 degree angle. That's it. That's hardly a BMX look. The picture below is a bike from one of the brands the OP is considering and it has a 7 degree sloping top tube, so even more than what Gord(and you apparently) find objectionable.
There is no right or wrong when it comes to anesthetics. If the bike below actually looks like a BMX to you, OK then. I think that's nuts, but oh well.
As for your comment about stiffness not being important...touring frames are historically built with thicker tubing in order to make them stiffer for handling more weight. I'm just not sure what to say to that.
If you want to be in God's corner, have at it. There is ample room over there.
