I think you are dismissing the "guarantee" of elite play for 3 years compared to nothing that is guaranteed, especially with injuries sapping careers that may never become anything. There is clear value in knowing what you get. I know injuries could happen to any of them, but that actually puts more value in the guy who is there right now. Also, many FF people think RG3 will be a better fantasy QB...I assume you are not one of them?
There are no guarantees in FF. Look at Peyton last year. Any player can get injured. I'd argue that old guys with older bodies and more mileage are more likely to get hurt than youngsters. So that might actually be a point in Luck's favor. If Brees or Brady goes down with another serious injury, their trade value will absolutely plummet. If Luck goes down, he's young enough that he can bounce back and still be in his prime ala Matt Stafford. And Luck is about 6'4" 235. Bigger and stronger than Brady and Brees, for whatever that's worth. I agree that there is clear value in knowing what you get. The problem is that you usually pay a premium for security because it is overvalued. Ironically, the more "proven" a player becomes, the more of his career you have already missed out on if you waited on the sidelines scared to pull the trigger.
Look at a guy like Ray Rice. When he was coming into the league, he would've cost you a middle round pick in a dynasty startup draft. Maybe a 6th-8th rounder. After his first season when he didn't get a ton of playing time, his cost would've been roughly the same. After his breakout year, his price would've jumped up into the late 1st-2nd round. And after logging two more elite seasons in 2010 and 2011, he has become widely regarded as one of the most untouchable assets in dynasty FF. The problem in all of this?
The longer you wait for someone to "prove" his true value, the more you miss out on his actual career. Rice's prime is halfway over. If you waited for him to prove himself before you acquired him, you not only watched his price increase, but you also missed out on some of his best production.
So if you buy Rice now, you are paying a premium based on what he has already accomplished. Yes, he is a safer pick than someone like Trent Richardson, but he is essentially "missing" three seasons from his prime. On the flipside, if you can identify these guys early and get in on the ground floor, you can often get them below their actual value and you also get to enjoy their entire career, and not just a fraction of it. The risk here is that the player in question never takes the next step. There are lots of guys like Beanie Wells, Kevin Jones, Vince Young, Matt Leinart, Jay Cutler, Braylon Edwards, Roy Williams, and Koren Robinson who never have the career that people expect.
That's why I think you have to be very careful in these situations and avoid paying top dollar for prospects until they've genuinely proven themselves unless they're truly special talents. Obviously making that distinction is easier said than done. There's no magical formula that determines who's legit and who isn't. It's a judgment call. Most of the time I would never recommend taking the "next big thing" over a current superstar, but...if you're absolutely certain about someone and you make the right call, you can reap a massive gain in value.
I think there are a couple guys in this class who qualify as special talents (Luck and Richardson) and I value them accordingly. I would also take a guy like Martin over more "proven" players because I think he offers more value at a lower cost. As for RGIII, I don't think he's as good as Luck and I think he's overvalued by a half notch right now.
