I don’t think I’ve noticed a difference between him speaking off the cuff and using a teleprompter, seems to do well either way to me.
Usually a leader will need to surround him/herself with good people and trust them to work out the details. In most circumstances, leaders just don’t have the time to get down to the dirty details on every issue. From what I’ve seen, Obama knows this. The last President that did a great job with this (IMHO) was Ronald Reagan…though I didn’t agree with some of his positions, I think he did a great job of finding quality people to work out details along the lines of his wishes.