I understand where you're coming from when you mentioned the word prototype. Some may confuse that terminology with the best since it has a similar ring to the word benchmark and benchmark is usually associated with the best of the best. I'm going to take a different path to your question and list the 5 prototype skills/requirement I foresee a player will need to have in the future at these positions. The game is evolving to the point where players are getting bigger, faster, and expanding their skills. Therefore, the limited but specialized skillsets, which plague these different areas of the game may eventually vanish down the road. So without further ado, here are my prototype trends for the future 5 positions in the NBA
Point Guard - Jason Kidd
Reason: The reason why I did not list Oscar Robertson or Magic Johnson was because they were taller than most (if not all) of the players at their position during their time, which made them more of an anomaly rather than the norm. I think it's rare that we'll see another point guard with Magic's height, who won't be moved to small forward (like LeBron) eventually. J-Kidd's height (6'4") is reasonably attainable for a point guard and should become a future trend for dominant floor generals. Kidd is not only a great passer but he is a very effective rebounder for a player his size. J-Kidd plays on both ends of the floor due to his ability to run the offense, shoot 3's, and accumulate steals. The one knock on Jason has always been his lack of scoring but with the game evolving to the point where guards are getting stronger and smarter, I believe that Kidd has the body frame and basketball IQ to adjust and dominate any era he plays in. Jason Kidd was an apprentice of Kevin Johnson in Phoenix and then went on to mentor Steve Nash in Dallas.
Shooting Guard - Michael Jordan
Reason: The only shooting guard in NBA history who has dominated a big man's game. MJ ruled an era that spawned some of the most dominant true (7 foot) centers the NBA has ever seen. Hakeem Olajuwon had to wait for Jordan's first retirement to get his only 2 rings. Shaq had to wait until MJ left for good to dominate the NBA. David Robinson couldn't land himself a title until Jordan left and Tim Duncan came on board. There are so many great players who retired without a ring (Stockton, K.Malone, Barkley, Ewing, Dominique, Kevin Johnson, Shawn Kemp, etc.) because of the man they call Air Jordan. MJ embodies everything you'd want in a prototype shooting guard. He has an enact ability to score from anywhere on the floor. He has unlimited elevation, a knack for scoring (or dunking) with authority, ability to get his teammates involved, and was a very clutch player. His defense was top notch (one of the few guards in history to win a Defensive Player of the Year Award) and he expected his teammates to perform with the same level of intensity as him every night. He held teammates accountable for their play and was a true class act.
Small Forward - Larry Bird
Reason: I didn't include LeBron James due to his lack of a consistent outside jumper. The Birdman was like a White Magic Johnson at the small forward slot. He wasn't the greatest man to man defender but he was great team defender. I believe that the average height for an NBA small forward in the future will be 6'8" or taller. These players must be able to mix it up in the paint as well as step outside and hit the open jumper. Bird fits this description. He was a great rebounder thanks to his size but he also had the playmaking ability to spread the ball and find the open man. He was also a heck of scorer and a dead-eye marksman who scored wherever and whenever he wanted to. MJ was once asked if he could choose a player besides himself to score the last shot with the game on the line and Jordan said without any hesitation - Larry Bird.
Power Forward - Kevin Garnett
Reason: Tim Duncan would have been an excellent choice here but since, I am predicting future trends, I believe that KG will be the perfect prototype for future power forwards. He has the height of a center (6'11") and the speed of a small forward. Garnett could posted up inside or step out and shoot from top of the key. He has the ability to get his teammates involved by passing out the double team and finding the open man. KG is a great defender and an underrated shotblocker. Garnett has been known to make his teammates better and possesses the right attitude to hold everyone accountable for their play without disrupting team chemistry.
Center - Hakeem Olajuwon
Reason: I agree with your selection because I have seen the Dream in action. I believe that Wilt had more of a size advantage and he had the playmaking skills of a point guard that nobody thought centers could ever possess. However, I doubt we'll ever see a center that skillful in the NBA ever again. The reason I chose Hakeem had a lot to do with his limited size and the way he utilized it to dominate great centers who were either taller (Robinson, Mutombo) or bigger than him (Ewing, Shaq). Centers in the NBA aren't as tall as they used to be (Dwight Howard, Al Horford, Kendrick Perkins). Then, you also have power forwards who play part-time center (Duncan, Garnett, Al Jefferson).
The only true 7 footers left in the NBA is Yao Ming and Greg Oden but they are considered a rare breed nowadays. The game has evolved towards a faster pace and centers need to be more quick and agile than before. That's why I believe that Olajuwon would have been more suited for today's game than a Shaq or Ewing. With small forwards and power forwards coming out of college taller and bigger than they were a decade ago, the demand for a true (7 foot) centers would be useful but isn't totally necessary as it was before when a majority of the NBA teams used to run a halfcourt offense. The Dream could do it all - score inside, pass it out to the open man, or hit the outside shot. Hakeem was also a havoc on D as a notorious steal artist and as well as a game-changing shotblocker.