An enrosque is balanced with both feet bearing the weight. This allows both feet to pivot simultaneously. Where the feet are placed doesn't really matter as it can be done in any position.
- enrosque: from enroscar. To coil, twist. While woman executes a molinete, man spins on one foot, hooking other foot behind the spinning foot.
Enrosque — From enroscar - to coil or twist: While the lady dances a molinete, the man pivots on his supporting foot, hooking or coiling the working leg behind or around in front of the supporting leg.
these are from tejastango and totango websites, and from my own experience.
so I don't agree with your view. You might get some leverage from the free foot but its still a pivot on one leg.