I came to yoga long ago because of an interest in buddhism. I went on from yoga to buddhist meditation and never got deeply into zen but studied what they said about padmasana, because they do take a lot of pride in it. The way they sit looks better but now, many years later and after haing read some of Iyengar’s thoughts on the subject (as presented in Light on pranayam) and having tried it myself both ways, I think they do it completely wrong.
The zen guys sit on a cushion and with their feet fairly low on the thighs, their ankles take a bit of a bend. Sitting on a cushion and with both knees touching the floor they have a stable enough triangle to sit on but with their feet low on the thighs they get none or very little of the support for the back that the pose is supposed to give and in fact need the pillow desperately to keep the back straight.
Sitting with the feet high up on the thighs, with the knees pointing more forward than outward, the pose gives a lot of support for the back and is extremely stable (I’ve fallen alseep in it and no, you don’t fall over) and somehow very light too. It looks less symmetrical though, the knees of the leg that is on top will probably not touch the ground. Put a small cushion under that knees if you need it then.