Say what you want about all the other numbers, but Marrero's power numbers have increased as he's climbed levels. From 16, to 17 to 18, so it's a small climb, but it's more difficult with each step up in competition. And, he's on pace for a career high in walk numbers, while having a career low in K's. He is showing improvements as a hitter. At 22, that's all you can hope for. He's not a superstar that will dominate a league, but he is getting better and showing legitimate big league ability as he does.
Even if he repeats AAA next year, he's someone to keep an eye on. I would agree he may seem like trade bait, but even if he sticks around, he's got the potential to impact the big club.