If he was a Top 10 talent due to his power tool alone (that’s what she said….), he would have gotten drafted in the Top 10 rounds last year.
What you think is super special and unique about him isn’t nearly as unique as you think it is. Take a guess where he finished in the SEC stat rankings in HR’s last year - his Jr year - which should have been his peak output season. Tied for 23rd, with at least 2 or 3 other players in the SEC. 25-26 other guys in the SEC alone that matched or exceeded his HR production. That’s just among 14 teams in one conference. Think about all the high school and other college talent that is also equal or better.
Now, when he makes contact, he hits it farther than most, but that only matters IF you can make contact. There’s a list a mile long of guys who could hit it 500 feet, but couldn’t ever register a 3-digit MLB batting average.
The worst part though, its all he does. He has little to no defensive value, can’t hit for average, is too undisciplined to get on base at a high clip with walks, can’t beat out double plays, etc. When you do one thing above average (but not elite), and do everything else below average, you don’t have much value at all to professional baseball.
Mangum was either the first or second 4th year player off the board in his Sr year. Totally different situation and very different from Hines. He was elite as a contact hitter (which isn’t valued very much by MLB anymore, unfortunately), and pretty good in just about every other area except power, which he has improved upon in the minors. He had a much more diverse and complete skill set than Hines, by far, and the fruits of that are now being seen with him at least on TB’s 40-man roster.