Neither LE nor prosecutors have said or even claim that Caylee's hands were bound. That important, because it means Caylee's hands would have been free to remove short strips of duct tape if they had cut off her ability to breathe.
Regarding the importance of the absence of long strips of duct tape, if a murderer planned to use duct tape as the instrument of death on a person whose hands were free, they would certainly want to make those strips of duct tape hard to remove -- such as wrapping them entirely around the victim's head.
As for Casey allegedly leaving Caylee's body on the surface of the ground near a road that is near the home, that certainly does not demonstrate planning, which is part of premeditation. Rather, that more properly points to the absence of a plan.
You're correct. Premeditation can form in a short period of time, but simply thinking that's what took place is not what's truly important. If prosecutors were to allege that at trial, what would be most important would be proving it happened that way. However, without an eyewitness or a confession, I doubt that is possible.
HTH