Since I bought the new girl, I've only done a minimum amount of touring (couple hundred miles in a day) but here's my $.02.
Weight: I'd say around the 450 pound wet range. It doesn't need to be superlight and I feel like a really light bike would feel noodly with 100lbs of gear and a pillion.
HP: this goes along I agree with Mr.Inc. This thing doesn't need to run a constant 150mph, but at the same time it has to have enough oomph for all the rider/gear weight plus the ability to get on it when a certain Victory rider decides he's got a bug up his ass
. 100hp, give or take? I guess top speed compared to power would depend on gearing too.
Torque: compared to a Monster I think a higher torque to HP ratio would be nice. Close to 80 or 90ft lbs
Price: Depending on options <20k
Engine Features: chain drive sounds good to me. Oh, and better than average stoppers. I had a pucker moment last weekend with give or take 40 lbs of gear, the GF on pillion, and an unexpected turn my buddy decided to take. I don't know too much else about engine goodies.
Extras (luggage, power outlets, etc): Power outlets, luggage (with one key), heated grips, adjustable suspension, good gel saddle, and hazards should be stock. I hate having to buy a bike like a Harley that comes with two wheels and an engine, then you have to chuck another 10k into it just to make it moderately functional. ABS, center stand
I'm basing most of this on my BMW so I'm not really taking looks into account. I'm goin more towards the functional aspect of the thing.
As far as the fairing issues people have been listing, I think a setup like ^^ is more efficient than your standard direct frame mount system. The one thing I don't like about the STx series is that your legs and upper body are totally exposed to airflow. Read: nice in summer, excruciating in winter. I've had the Beemer on 2 hour highway runs at 20F with no issues other than a bit of hand discomfort (old heated grips, not as great as they used to be) and I couldn't imagine doing the same on the Monster or any other partially faired bike for that matter.
I also agree with Double Eagle. I realize Ducati is a "sports bike" company, but I've seen guys hustle some pretty good sized bikes through the twisties with no problem. As long as they beef up the suspension/brakes/engine a bit, it will run just fine with the rest of them.