I'll let Peter Gammons introduce his annual exercise here:
In the closing days of March annually, I poll general managers, scouts,
managers and other baseball sages on a number of spring training
observations. The first was: “Were there any young players you watched
and said, ‘this guy has a chance to be a star?’”
Not to give anything away, but Carlos Correa came in #1. Gammons:
Scary skills, highly intelligent, work ethic off the scales, 6-3, but
putting him in Lancaster may create bad hitting habits that set him
back.
I'll disagree with that last part. What we've seen is that Luhnow simply doesn't believe in skipping levels. Also, if you recall our posts from last season, the Astros seem to be interested in (and this is my speculation) making sure their top prospects make it to all the minor-league affiliates and, by extension, their fan bases. See Appel, Mark; Springer, George, and Singleton, Jon (remember when he was reinstated after the 50-game suspension, he started at Quad Cities).
There is an interesting note on Byron Buxton:
One very good evaluator thinks “George Springer’s best six years will be
better than Buxton’s six best but Buxton’s career may be 15 years of
excellence.”