FWIW, I don't think many people saw a 30 HR season coming from Jacoby Ellsbury last season. Those who claim to have are probably lying.
Your SP seem more like "if they ever put it together" guys instead of should have seen it coming. We've pretty much seen what they have to offer, but they each offer inherent flaws that have prevented them from elevating their games to an elite level. Hindsight is always 20/20, but these aren't guys we're necessarily expecting to elevate their game as much as we've identified them as guys who possess the skills to one day do it if they can get past their individual stumbling blocks.
Bruce I see as, similarly to Giancarlo Stanton, a guy who offers tremendous power upside but not a ton else. He's a .260 hitter and if he hits above that, it's probably BABIP related, as seen in 2010. I don't expect to see .280 again unless he changes something. So yeah, he may approach or even surpass 35 HR this season, but he'll likely do it batting .260, chip in 5 - 10 SB, maybe reach 100 RBI, but if he bats 5th he's likely not going to approach the 90 Run mark. Even batting 4th he may struggle to. So yeah his upside is excellent, but I don't think anybody has doubted that since he was called up, and he's not exactly being overlooked when his Median Draft Position is at the beginning of the 4th Round.
Hosmer has the potential to put up a Vottoesque line, but again, nobody's sleeping on it, he's being drafted in 5th Round, and it's much more likely that he has his ups and downs this season and disappoints given some of the lofty expectations being put on him, than become a massive value.
For candidates for me, I see possibilities of...
Brett Lawrie -- similar thing could be said about him as Hosmer, but 3B doesn't have the elite players that 1B does in terms of depth, and Lawrie could very easily place himself in the Top 2 or 3 in that position without even reaching his ceiling this season.
Andrew McCutchen -- could easily find himself outperforming the Gonzalezes, Ellsburys, Grandersons, etc. of the world. Is every bit the 30/30 candidate that any of them are. Being drafted in the late-2nd/early-3rd Round, but it's rare you're going to find a guy being drafted too too low who may end up one of the Top 5 or so players in the game.
Alex Rodriguez -- he's been banged up and we've forgotten just how good he is. His production will rely entirely on his health, which prospects aren't wonderful on, but the treatment he got has worked just fine for Kobe, so that's a little encouraging. In the 5th Round he's still got the potential to give you 30 maybe even 35 HR in that ballpark, bat .280, and surpass both 100 Runs and RBIs. Dude managed 67 and 62 last season in just 99 games. He's just 2 seasons removed from a 125 RBI campaign.
Carl Crawford -- remember when he was drafted in the 1st Round last year? That wasn't by accident. No reason he can't approach 15 HR and 60 SB like he did with Tampa in '09 or 19/47 like in '10. When the end of the season rolls around, I think we're much more likely to see a season that mirrors the rest of his career arc thus far than last season's disappointment, and he's being drafted in Round 5.
Stephen Strasburg -- obvious statement is obvious.