I don't entirely agree with this. Listi ended at Reading second half of his age 24 season. Walding had 25 HR and a higher OPS (.842) at Reading at 24, but this past season he upped his OPS at LV to .864. Not many of the Reading wonders (and neither Walding nor Listi has a high enough OPS at Reading to qualify as a true Reading wonder) improve their OPS going on to Allentown. Walding's big problem has been staying healthy and getting 400 AB a season. Also, not the plus 3B glove man he was expected to be when drafted. Walding's ascent the past two seasons has been fairly steep. A guy I expect to lose in the Rule 5. The biggest plus on Listi was what he did first half of last season at CLW -- truly plus offensive numbers; he wasn't nearly as good a at Reading. Really, I don't give him any extra credit for being drafted at age 23, really the reverse -- I tend, perhaps unfairly, to question the professional baseball commitment of guys who stay in college until age 23, thus harming their chance by their own actions.
Zach Green's career even more seriously hampered by injury, but had a breakout season at age 24, which took him from Reading to Allentown. His Reading numbers (.953 OPS) makes him the most legit bat prospect among Listi, Walding, himself. He is same age as Listi and a level ahead.
Hall still shows the best bat potential of all these guys. He wasn't ready for Reading at age 22, but put up very good CLW numbers.
All of these guys are destined to be 1B, so they have to be better than Hoskins to start in Philly, although they can be productive bench bats at low cost.