If anybody was wondering why the WWE chose the 6 Rookies that they did, here's my reasons why. I thought they had more than that to choose from, but it was actually a pretty easy decision.
Season 1
David Otunga (2nd), Justin Gabriel (3rd), Heath Slater (4th) & Daniel Bryan (7th)
All of the above superstars have appeared frequently on RAW or Smackdown since the end of NXT1. All have been champions and all have futures with the company that's for sure.
Skip Sheffield (6th)
Was a big part of the Nexus as he was the main muscle but has been out injured since August I think. Apparently Vince McMahon has major confidence in Sheffield, so when he returns after Wrestlemania he will likely be used prominently on RAW.
Michael Tarver (7th)
Tarver was beginning to build a reputation for himself and was just beginning to garner frequent heat from the crowd before being injured. He has made a few backstage cameos for both brands recently, which suggested the WWE could have something going for him (or at least he's in their minds) but he has since been moved back to FCW. I think the WWE may have something planned for him, so if that's the case NXT5 would just hinder his progress.
Darren Young (5th)
Being kicked out of the Nexus just weeks after it's inception had Young's career on the ropes, for a while he was nowhere to be found. He started making appearances on Superstars, wrestling some good matches, but they weren't frequent enough. It was obvious from the beginning that the WWE had absolutely nothing for Young, but they knew he had potential and deserved something. NXT5 is his chance to shine and really earn himself a following, so he was the logical choice from this season.
Season 2
Michael McGillicutty (2nd), Alex Riley (3rd) & Husky Harris (4th)
McGillicutty & Harris were members of the Nexus but have now been "put on the shelf" thanks to being punted by Randy Orton. WWE already have plans for McGillicutty as he is being "re-packaged" and Harris is being given more time to develop, so NXT5 would be a major step back for both. As for Riley, he was the WWE Champion's protege for months and is now being re-packaged also, so he has a bright future as well.
Percy Watson (5th)
Watson has been wrestling dark match after dark match, and winning them all as well, and is also considered the most athletic performer that FCW has. Due to the constant dark matches, it's clear the WWE has plans to elevate him to the main roster after Wrestlemania, so NXT5 would be a step back.
Lucky Cannon (6th) & Titus O'Neil (8th)
These two have been chosen for NXT5 and have had some success in FCW since NXT2 ended. Cannon has become a heel and using his good looks as the base of his heel persona, helping him become the current FCW Heavyweight Champion. Titus is one half of the current FCW Tag Team Champions, so both men must have impressed if they are being rewarded with titles, so being chosen for NXT5 makes sense.
Eli Cottonwood (7th)
Now Cottonwood would have been up for consideration for a spot, but I am very glad he didn't get it. Not a fan of him at all as he is a bad wrestler, is bad on the mic and is not entertaining in the slightest.
Season 4
Brodus Clay (2nd)
Clay was clearly the standout on NXT4 and is currently Alberto Del Rio's "enforcer" I guess you could put it. He's really in the same position Riley was with The Miz and has also proven he has what it takes to make a name for himself in the WWE.
Derrick Bateman (3rd)
Often the crowd favourite, Bateman is entertaining, charismatic, is great on the mic and is a decent wrestler. It's clear WWE may have something planned for him if he is not on NXT5, so that is very good to hear. I wouldn't like to see him on NXT5 anyway, he has proven himself enough in my eyes.
Byron Saxton (4th), Conor O'Brian (5th) & Jacob Novak (6th)
These three are all fresh in our minds and didn't make enough of an impact to warrant being in consideration for a future spot on a WWE roster. I see Saxton as the one with the least to prove, Novak with a lot to prove and obviously O'Brian would be in the middle. After seeing O'Brian's video package, I now wish him the most success as it sounds like he has had a very tough life. Personally I'm a sapp for heart-warming stories like O'Brian's, but he still needs to step it up. All three make plenty of sense.
Overall, I think Lucky Cannon and Titus O'Neil were obvious choices as they seem to be two of the three best that FCW has, which means they must have improved since NXT2. Byron Saxton, Conor O'Brian and Jacob Novak would've been in the same position as Cannon & O'Neil - looking to improve in hope of another future opportunity - if NXT5 wasn't a redemption season. Clearly Young is just being given a lifeline, which I would rather than have Cottonwood appear.
I still think that Cannon or Saxton will win the season, but Young has definitely put a strong case forward already and is leading the competition after the first week.