no connections to a trusted potential cofounder - may as well have a cofounder in this case to ease the initial burden and offer support down the road
able to use good programming practice when it doesn't seem imminently necessary - if there is any hope of code being understandable to anyone but yourself (and even yourself, several months down the road), good documentation and clean interfaces are important. With no need to work with anyone else initially, it will take some discipline to uphold this practice
passion for the project or idea - something has to keep you going when doing the drudge work or when a wrench gets thrown in the works, and you only have yourself to turn to for a reminder of why you started this whole thing in the first place
good vision and leadership - the whole crux of your assertion is that having a single founder eliminates disputes in the decision-making process. Obviously the single founder better make good decisions and be able to get others on board with those decisions
good judge of character - with employees being expected to fill many of the roles that a cofounder would, it becomes especially important to hire the right employees, the kind who will give valuable input in every aspect of the project
good people skills - all of the first several employees need to have the feeling that they can approach you and give you their opinions and ideas on many aspects of the company, while being assured that you are taking their input seriously. This can help mitigate bad decisions and prevent tunnel vision while getting the most out of your employees by keeping their morale up
mentally stable - this may seem like a given, but a single founder will have to be able to run on an especially even keel in spite of having numerous setbacks and high levels of stress. It would be good if that thinking out loud did not turn into having conversations out loud with yourself ;)
hard worker - able to do all of the initial work alone, meeting self-imposed deadlines along the way and to setting a good example for the initial employees to live up to
an engaging personality - something to convince those employees that they should stick with you even when the whole idea is looking crazy and doomed. Also, a way to hire those awesome employees that you found thanks to your good judge of character
confidence - at no time can you seriously doubt your ability to come through or to lead everyone, or the project is doomed with no one else to (even temporarily) take over the reigns
So it seems, based on my own little analysis here, that being a successful single founder depends on the person having a lot of intersecting advantageous traits. Of course, some of these are also necessary in a cofounder situation, and some of them can be learned or improved with time, so things may not be as grim as they initially seem. Can we agree, though, that the ability to successfully and independently found a company requires the right kind of person, a stronger individual than the type who might be successful in a two-founder project?
I would agree, though, that if you have all these traits, you have a good chance of being better off on your own (dissenters: do note the first trait I mentioned). I would really like to think that I meet most of this criteria, with some things that I need to work on before I'm ready to take a solo dive, and I know that I would prefer to work alone. I will certainly keep your advice as inspiration to remind me that it's definitely possible for me to do this sort of thing by myself.