If you map out the NBA, Power Forwards ARE the most plentiful position. There is just a GIANT supply of them.
These are the 2012-2013 Active NBA players.
Out of the 23 hybrid Forward players about 95% of them are SF/PF hybrids. So technicaly about 99 possible PFs are available. Out of the 20 hybrid Guards, about 6 or 7 are true PGs.
So the two most plentiful positions (>90) are PFs and PGs.
They beat the other positions by 20-10 more players every year. So that means that power forwards are 10% more likely to find a suitable candidate than say SG. (I refuse to do the math. All I know is that there is a greater chance.)
But in the case of the Rockets, where PARSONS is the best power forward, you need someone who can shoot, dribble, defend, and REBOUND. You basically want a hardy high production SF such as a Lebron, Paul George, or young Gerald Wallace. And that is what limits the playing field.
Using Wins Produced 48 (I don't care if you don't like it, I do.), I made a list with certain cut offs. You gotta finish well, you gotta rebound, and you got to generate superstar like wins.
So my list, in no particular order happens to be...
Utah's Jeremy Evans and Demarre Carroll, Twolves' Andrei Kirilenko, Sixers' Moultrie and D. Wright, Toronto's Quincy Acy, Memphis' Ed Davis, Dallas' Brandan Wright, Laker's Jordan Hill, and the Pelican's Aminu,
Out of all these teams, only Evans, Carroll, Kirilenko, Moultrie, and Wright have any long range shooting ability. And only Kirilenko, Caroll, and Wright have any long range ability. Acy, Moultrie and Evans have the best eFG% but they have haven't played MORE than 200 minutes in their entire careers.
So if you really boil it down. If we're looking for versatile, we're looking at Dorell Wright,D. Carroll or Kirilenko. I doubt the Timberwolves will give up Kirilenko but he is old. (who knows?)
If we're looking for another Tiago Splitter Center/PF, we're looking at Ed Davis.
If you boil it down further for age, fewer personal fouls, we're looking at Dorell Wright and Ed Davis. Those are the safer bets.
As for the rooks, there is a possibility of J. Evans breaking out...but his college scores doesn't trend that way. Acy and Moultrie college scores are even worse than Evans.
What is the point? If you did this exercise for Shooting Guard, you wouldn't have a list. There are basically no Shooting Guards in the NBA that is up for contract. None. Most PGs nowadays have to fulfill the SG role BECAUSE there ARE no shooting guards that can give you steals, eFG%, and free throws. Kobe, Wade, Harden. That is your top and only 3 SGs in the entirety of the NBA. The 4th SG rank belongs in D-league, really. It would be better to put a high producing PG in that area even if you sacrifice rebounds. Small-ball is less about having a quicker center than it is having a overachieving PG at SG, and asking your underperforming SG to go grab more rebounds.
You would also have a short list at Center. Not quite as bad at SG but very similar.
All in all, Morey addressed the two positions where the market supply is vastly inferior to demand.
As for PF, I wouldn't worry. There's a bunch coming this draft. And more than a few choices to be had during the next round of trades. Thomas Robinson is a really great trade chip.