I bolded the ones I believe will be/are as good or better production wise than Yonder over the next 5 years or so strictly with the bat IF Yonder cuts down his swing a bit. There are a few I am on the fence about because I haven't studied them/their issues or lack thereof like Smoak, Morrison, Gaby Sanchez, Kila K., Rizzo and Viciedo. But others are fading (ex. Helton) or haven't shown enough yet (Soto) or I have seen enough and am not overly impressed (Butler, Ike Davis, Loney, Sandoval, Kotchman, Edwin) or not impressed at all (Francisco, Chris Davis, Brett Wallace, B. Allen, Borchering, Blanks). There are also some of those guys I don't know at all like Goldschmidt, Streiby, Trumbo.
Bottom line I would rate Alonso as a top 15-20 1B in all of pro ball right now because I believe he can hit for power, average & discipline with a bit of coaching. In fact I despise the fact the people want to pigeon hole the guy into a Sean Casey type of mold because he hasn't hit for tons of power in the minors...yet. I will blame all of that on his hand injury and assuming health I do expect him to hit for lots of power in Louisville this season, then the "experts" will give him a fast ascension up the ranks come mid season/late season.
The only question for me is can that translate to the bigs and none of these other big name prospects have proven that yet either. So until there is some seperation I will put him on the list if not near the top of it when it comes to minor league 1B prospects.