A full set of heated garments uses a lot more than the 35-77W mentioned in that link.
I read the article as showing that most heated garments (gloves, vests, pants liners, etc.) use between 35-77W - individually, not as a full set. Not everyone likes to ride a motorcycle in sub-freezing temps with heated footsie pajamas under their riding gear
I have a set of Powerlet heated gloves that are listed as drawing up to 24W/pair that I use all the time (instead of heated grips), and a rarely used Powerlet jacket liner that can draw as much as 105W but has a setting to top out at 60W. My electrical accessories are otherwise pure stock equipment, which I will assume is about the same as the earlier DL650s in draw - headlights, tail lights, etc., - maybe a little higher for the digital dash.
So if the 2002 V-Strom had an excess capacity of 75W, and the 2007+ bikes bumped up the alternator output by 40W (360W to 400W), then I'm guessing there is about 100W of excess capacity on the stock 2012 DL650AL2. Not a lot, but enough to safely use my gloves and liner at the 60W setting, or possibly the jacket at the higher setting but dialed down with the controller.