It's not impossible to see Parker going as low as 6th anymore. Bowing out of the tournament in the first round with a rough game doesn't help but it's more than that as he hasn't looked like a elite prospect in terms of decision making and athleticism for a while even though his stats have been pretty good. Being in shape in workouts are going to be huge for him, which is sort of crazy for a player who has been highly touted for a long time with plenty of game tape to go on.
Wiggins and Embiid have to be above him. I bet Exum will be too. His profile--6'5 to 6'6, lean, lengthy, rangy prototypical basketball player body, passer, transition threat, dribble penetrator, above average athleticism or more, possible point guard--pops much more on paper than Parker's. Potential ceiling weighs really heavily that high in the draft. It might come down to whether Exum and his agent find the teams selecting fourth or fifth more appealing and adjusts his workout schedule accordingly. Since workouts are going to be huge for a player with such limited exposure, that could be the difference.
Parker and Randle have somewhat similar warts with questions about their defense and ability to finish in the paint. A team could easily prefer Randle more. If Smart has a huge tournament, he could possibly overtake Parker as well.