Crown Royal nailed this topic.
This reminds me a little bit of the Randy Moss debate. Moss enters the league, and suddenly everyone wants a tall, fast receiver like that. Ugh....they're not exactly easy to find. Especially good ones.
Now, I don't know if Watkins will ever amount to anything other than a training camp body. But in terms of pure size/speed ratio -- and NOT NFL talent, since we can't yet judge that -- I'd imagine it'd be difficult to find free safeties like him.
Yeah, it's a copy-cat league, but if he does ever become productive, how do you replicate players like him physically?