SmilingNage, thank you for bringing this again to us. Actually the one being impolite was her. Here, read:
1. Uke will not land on your leg by doing a proper Aikido Koshi Nage a la O'Sensei, i.e. with "that" swinging motion.
2. One footed, cross-legged, heels together or shoulder width apart, if tori is smaller than uke, he (generic he) must bend the knees... but the goal is to keep your hip under uke's, not bending the knees per se.
3. It's not tripping but swinging uke over tori's hips. Nothing to do with Judo. Not that Judo's way is wrong, though.
Maybe we misunderstand each other, I believe we were talking about close or wide stance. So let me try to clear it up the best I can.
If you throw with a wide stance in most koshi nages applications, the likely hood of nage coming down on your knee/leg is much higher, that is a fact.
Actually bend the knees should be more of a flexing of the knees to load uke on to your koshi. So you can scoop him up with your hip motion. Otherwise You cant get under uke's center without flexing or bending at the knees. Uke will most likely run into your back and not be loaded probably.
With a wide stance its harder to get both "cheeks" into the throw. Most often only one cheek gets into the throw. Making it more akin to a judo sweep/throw.