This is similar to projecting college recruiting classes. There comes a time when prospects get to play and all the projections don't matter at that point. We'll know the farm system is getting better when "prospects"(or suspects) start having an impact at the major league level or they get turned into something that impacts at the major league level.
Where the Reds system ranks isn't really worth debating. Just start graduating impact players and most won't care where those players or the system was ranked.